Accelerators for curing phenolic resole resins

ABSTRACT

There are disclosed methods and compositions for accelerating the hardening of phenolic resole resins having a pH of about 4.5 to 9.5 with lightburned magnesium oxide or magnesium hydroxide, with or without the addition of an ester functional hardening agent. Acceleration of hardening is achieved by incorporating into said compositions an effective quantity of a material which: increases the solubility of magnesium in the hardenable mixture; by certain amines; or by certain chelating agents. Accelerator compounds include those which provide chloride, sulfamate, nitrate, formate, and phosphite anions as well as selected tertiary amines.

This application is a divisional of my application Ser. No. 07/995,968which was filed on Dec. 23, 1992, now Pat. No. 5,223,554 which in turnis a divisional of my application Ser. No. 07/943,065 which was filed onSep. 10, 1992, now Pat. No. 5,214,079 which in turn is a divisional ofmy application Ser. No. 07/616,879 which was filed on Nov. 21, 1990, nowU.S. Pat. No. 5,182,346 of Jan. 26, 1993, which in turn is acontinuation-in-part of my patent application Ser. No. 07/562,206 whichwas filed on Aug. 2, 1990, now U.S. Pat. No. 5,096,983 of Mar. 17, 1992.

BACKGROUND OF THE INVENTION

This invention relates to methods and compositions for accelerating thehardening of phenolic resole resin binder compositions which arehardened with magnesium oxide or magnesium hydroxide alone or togetherwith an ester functional hardening agent. Such hardening can take placeat about room temperature.

It is often desirable to accelerate or shorten the time it takes forphenolic resole resins to harden by the use of a lightburned magnesiumoxide or magnesium hydroxide hardener, alone or together with an esterfunctional hardening agent, particularly if such acceleration does notsignificantly affect the eventual hardness, tensile strength, and otherdesirable properties of the hardened or cured resin. This isparticularly the case in cooler climates and lower temperatures.

Magnesium oxide or hydroxide, with or without an ester functionalhardening agent, are used as the hardening agents in this invention.

Applicant has found that the hardening of phenolic resole resincompositions admixed with hardening quantities of lightburned magnesiumoxide or magnesium hydroxide, either alone or together with an esterfunctional hardening agent can be accelerated by use of certain aminesor compounds which increase the solubility of magnesium from thehardener which is admixed with the resin. Illustrative of acceleratorsare compounds which provide anions of chloride, sulfate, nitrate, andsulfamate as well as various amino compounds such as2,4,6-tris(dimethylaminomethyl)phenol.

Lightburned magnesium oxide and magnesium hydroxide are well known roomtemperature hardening agents for phenolic resole resins. Furthermore,magnesium oxide and magnesium hydroxide are used as the condensationcatalysts for the manufacture of phenolformaldehyde resole resins fromphenol and formaldehyde. Additionally, relatively inactive magnesia,e.g., periclase or refractory grade magnesia, is a conventionalrefractory which is often bound into various shapes with phenolic resoleresins; however the periclase is relatively inactive and is not used asa hardener. Illustrative of references which disclose the use ofmagnesium oxide or magnesium hydroxide to harden phenolic resole resinsin various types of compositions, there can be mentioned U.S. Pat. Nos.2,869,194 of Jan. 20, 1959 to R. H. Cooper; 2,869,196 of Jan. 20, 1959to R. H. Cooper; 2,913,787 of Nov. 24, 1959 to R. H. Cooper; 3,666,703of May 30, 1972 to T. Murata et al; 2,712,533 of Jul. 5, 1955 to J. S.Mitchell; 2,424,787 of Jul. 29, 1947 to W. H. Adams, Jr.; and 4,794,051of Dec. 27, 1988 to M. K. Gupta.

The U.S. Pat. No. 4,794,051 Gupta patent also mentions the use of aclass of ester functional hardening agents namely, lactones, which areused together with the magnesium hardeners, but preferably in admixturewith calcium hardeners. The U.S. Pat. No. 2,869,194 Cooper patent alsomentions that magnesium oxychloride and magnesium oxysulfate, which canbe prepared by mixing magnesium oxide powder with an aqueous solution ofmagnesium chloride or its equivalent or magnesium sulfate or itsequivalent, frequently provide shorter hardening times as compared tothe magnesium oxide alone. The U.S. Pat. No. 2,913,787 Cooper patentalso mentions the optional inclusion in his compositions of "novolaktype" phenolics as well as optional inclusion of hexamethylene tetramineor equivalent curing agent or accelerator for phenolic resins, includingethylene diamine, diethylene triamine and the like relatively lowmolecular weight polyamines and paraformaldehyde.

U.S. patent application Ser. No. 450,989 entitled "Phenolic ResinCompositions" filed Dec. 15, 1989, now U.S. Pat. No. 5,051,454 with P.H. R. B. Lemon, J. King, H. Leoni, G. Murray, and A. H. Gerber asinventors, which is based on GB 8829984.7 filed Dec. 22, 1988, disclosesthe preparation of phenolic resole resins with alkali or alkaline earthmetal compounds as the basic catalyst and the subsequent roomtemperature hardening of such resins with an esterified phenolic as theester functional hardening agent together with various bases, includingoxides and hydroxides of magnesium and calcium.

European Patent Application Publication Number 0094165, which waspublished on Nov. 16, 1983 with P. H. R. B. Lemon et al as inventors,has broad recitations which mention the use of various alkalinematerials including magnesium oxide (magnesia) for condensing phenol andformaldehyde to form phenol-formaldehyde resins and for furtherincreasing the alkalinity of such resins which use ester functionalagents for hardening the phenolic resin. European Patent ApplicationPublication No. 0243,172, now U.S. Pat. No. 4,831,067 of May 16, 1989,which was published on Oct. 28, 1987 and lists P. H. R. B. Lemon et alas inventors, has recitations similar to those of the above-mentioned0094165 publication.

U.S. Pat. No. 4,939,188, which issued on Jul. 3, 1990 with A. H. Gerberas inventor, discloses the use of lithium ion generating alkalizingagents in resole resin binder compositions which, when hardened by anester functional curing agent, exhibit tensile and compressive strengthssuperior to that obtained from compositions using sodium or potassiumion generating alkalizing agents.

U.S. Pat. No. 4,011,186 of Mar. 8, 1977 to Higgenbottom as well as U.S.Pat. No. 4,216,295 of Aug. 5, 1980 to Dahms relate to phenolic resolescatalyzed with alkaline earth metal hydroxides and neutralized withoxalic acid or its acid salts which provide stable, inert, insolubleoxalate salts dispersed in said resole and, additionally increases theviscosity of the resole resin.

U.S. Pat. No. 3,624,247 of Nov. 30, 1971 to Gladney et al relates to theremoval of residual calcium catalyst used in the production of phenolicresins. The residual calcium catalyst is removed by treatment with analkaline solution of an ammonium salt which forms an insoluble salt withcalcium upon pH adjustment. Soluble ammonium compounds used in theprocess of the 247 patent are listed as sulfate, phosphate, andcarbonate.

U.S. Pat. Nos. Re 32,720 of Jul. 26, 1988 and Re 32,812 of Dec. 27, 1988to P. H. R. B. Lemon et al are further illustrative of the literaturewhich discloses room temperature hardening of highly alkalinephenol-formaldehyde resole resins with an ester hardening (curing)agent.

Japanese Kokoi Tokkyo Koho JP 60/90251 of May 21, 1985 to KyushuRefractories Co., Ltd., which discloses the cold-hardening of athermosetting resole resin by the use of ethylene carbonate andmagnesium oxide.

My initially mentioned parent patent application Ser. No. 07/562206discloses materials such as various anions for retarding the hardeningof phenolic resole resins with magnesium hardening agents.

SUMMARY OF THE INVENTION

It has now been found that the room temperature hardening of phenolicresole resin compositions admixed with hardening quantities oflightburned magnesium oxide or magnesium hydroxide, either alone ortogether with an ester functional hardening agent, can be acceleratedwith certain amines or with materials which increase the solubility ofmagnesium in the reaction mixture. Further, it has been found that: theuse of a relatively low surface area lightburned magnesium oxide whenadmixed with a higher surface area magnesium oxide has little effect inaccelerating the hardening of the phenolic composition beyond that dueto the high surface area material but provides greater strength to thecomposition on thermal curing; the use of lithium carbonate is both anaccelerator and a strength improver in the phenolic composition; andwhen sulfamate accelerators are used with low molecular weightphenolics, having a high free phenol content; the strength of thecomposition is improved. The phenolic resole resins used in thisinvention generally have a pH of about 4.5 to 9.5.

In one aspect of the invention, compositions and methods for preparingbinders having a shortened hardening time are provided by mixing thephenolic resole resin with a magnesium hardening agent with or withoutan ester functional hardening agent and an accelerator.

In another aspect of this invention, the above-mentioned compositionsand methods together with an aggregate are used for patching orresurfacing various rigid substrates such as concrete and asphalticstructures.

In another aspect, a shaped article is provided; the shaped articlecomprising an aggregate material bonded together by a resin binder; thebinder comprising a hardened phenol-formaldehyde resin hardened in thepresence of a magnesium hardening agent and an accelerator, with orwithout an ester functional hardener.

Illustrative of accelerators, there can be mentioned materials whichprovide anions of chloride, sulfate, nitrate, sulfamate, phosphites,corresponding acid addition salts of basic nitrogen compounds andcompounds of the formula: ##STR1## wherein: X is a lower aliphatichydrocarbon group, R¹ and R² are alkyl or together with the nitrogen towhich they are attached form a heterocycle and R³ and R⁴ can behydrogen, alkyl, or when R³ and R⁴ are taken together with the nitrogento which they are attached form a heterocyclic group.

Advantages

The processes and compositions of this invention provide a means foraccelerating the rate of hardening of phenolic resole resins withmagnesium hardening agents over a wide temperature range such as about60° F. to 120° F. by use of small amounts of amines or various chemicalswhich increase the solubility of magnesium in the binder composition andaccelerate the hardening of the resin. One of the variables affectingthe rate of hardening of phenolic resole resins is temperature. Lowertemperatures decrease the rate of hardening. Therefore, by use of theaccelerators of this invention, the hardening rate can be acceleratedover a wide range of temperatures such as room or ambient temperatures,particularly in cooler climates or work places having lowertemperatures. By use of the accelerators of this invention, thehardening rate can be accelerated at low temperatures in order tomaintain a desirable processing time while developing adequate strength.

The methods and compositions of this invention can also affect reactionrate of the phenolic resole resin by selection of surface area of themagnesia to be used, by choice of the specific accelerator, and,optionally, by choice of the specific ester as well as the quantities ofthe hardeners and accelerators.

Preferred methods and compositions of this invention utilize an esterfunctional hardening agent together with the magnesium hardening agentsince the reaction rate of phenolic compositions are strongly affectedwhen an ester is used with the lightburned magnesia or magnesiumhydroxide hardener together with an accelerator. Furthermore, thehardened phenolic resole resins, which use both a magnesium hardeningagent and an ester functional hardening agent, have greater compressiveand tensile strengths as well as greater resistance to aqueous organicacids as compared to phenolic resole resins which have been hardenedonly with magnesium oxide or magnesium hydroxide.

The methods and compositions of this invention possess many advantagesas compared to curing of phenolic resole resins with esters alone asshown in U.S. Pat. No. Re 32,720 of Jul. 26, 1988 to Lemon et al andU.S. Pat. No. Re 32,812 of Dec. 27, 1988 to Lemon et al. The processesand compositions of those patents require alkali metal hydroxides andfor practical applications, the resins have a pH of greater than 12. Incontrast to those patents, the present invention involves substantiallylower pH values, and there is no need for alkali metal hydroxides orsalts. The compositions and methods of the present invention have manyadvantages over those which do require high alkalinity, e.g., pH of 10or 12 or more, particularly in view of the high alkali metalconcentration required for the highly alkaline compositions.Illustratively, the phenolics of the present invention have: Bettershelf stability; improved stability of resin color in relation to timeand exposure to the atmosphere; lower viscosities at higher solidslevels which, among other things, increases wettability of aggregate orsubstrate which, in turn, increases bond strength; safer material andwaste handling properties; a higher density and less porosity on curingat the higher solids levels for resin, compositions, e.g., such as thosecontaining aggregate which, in turn, increases strength and resistanceto solvents and aqueous media; and improved stability with aggregatesnormally attacked by sodium or potassium at a high pH and improvedstability to glass or polyester fiber. Excess alkali can result instrength loss, e.g., see Lemon et al Re 32,812, Table 4, wherein theeffect of KOH/phenol molar ratio shows steady decrease in compressivestrength of resoles as the mole ratio is increased from 0.68 (5032 psi)to 1.02 (4271 psi). In contrast to this, an excess of the magnesiumhardener can increase strength and also insolubility of the finalcomposite because of the divalent cross linking by magnesium incomparison with chain termination by use of sodium or potassiumalkalies.

Accelerators are also advantageous for reducing the strip time of moldedor cast materials or simply to increase the hardening rate, particularlywhen temperatures are significantly below 70° F.

DETAILED DESCRIPTION OF THE INVENTION Magnesium Oxide and MagnesiumHydroxide Hardening Agents

The term "accelerator" as used herein refers to a material which speedsup, hastens, or simply accelerates gelation or hardening of the phenolicresole resin in the methods and compositions of this invention such asthe hardenable binders which contain the phenolic resole resin, amagnesium hardener, and optionally an ester functional hardening agent.Some of the accelerators of this invention appear to work by increasingthe amount of magnesium or magnesium compound in solution, i.e., bychanging the solubility of magnesium compound in the hardenable mixture.

The term "hardening agent" is used herein to denote a material whichincreases the rate of hardening of a phenolic resole resin, e.g., atroom or ambient temperature (R.T.). Hardening is attained with increasesin viscosity and gelation to form a solid which is firm to the touch andgenerally inflexible. The hardenable binder compositions of thisinvention which contain a phenolic resole resin, magnesium hardener andoptionally an ester functional hardening agent but without anaccelerator will generally be hard within about 24 hours of standing at75° F. Although such hardening can also be referred to as "curing," the"hardening" or "curing" with hardening agents does not develop thetensile and compressive strengths of a thermal cure.

By the term "room temperature hardening" we mean the hardening ofcompositions of this invention at temperature of about 60° F. to 90° F.,particularly about 65° F. to 80° F. However, the use of accelerators inthe processes and compositions of this invention accelerate thehardening of compositions of this invention at lower and highertemperatures such as 60° F. to 120° F. In addition to room temperaturehardening, or hardening at ambient temperatures such as those of about60° F. to 120° F., the compositions of this invention can be thermallycured after hardening by the hardening agents or the compositions can bethermally cured prior to such hardening. The term "thermal curing" asused herein means curing of the composition at a temperature of at least170° F. and generally at a temperature of at least 212° F.

The magnesium hardening agents are magnesium hydroxide, lightburnedmagnesium oxide, or other magnesium oxide which has the hardeningactivity for phenolic resole resins of lightburned magnesium oxide suchas that having a surface area of at least 10 square meters per gram (10m² /g). Lightburned magnesium oxide is the preferred magnesium hardeningagent because magnesium hydroxide gives lower strengths to the hardenedcompositions.

Small quantities of calcium hydroxide, calcium oxide, or calcineddolomite (doloma) can also be added as a hardening agent. However, theuse of calcium oxide, calcined dolomite, or calcium hydroxide alone orin high quantities together with the magnesium hardeners have seriousshortcomings. Thus, calcium based oxides, including calcined dolomite,or hydroxides are highly basic and react too quickly, thus greatlyreducing the mix working time. However, minor quantities, e.g., fromabout 1% to less than 50% by weight based on the weight of the magnesiumhardening agent, of these calcium containing compounds, when mixed withthe magnesium hardening agents, can be used to replace an equivalentweight of the magnesium hardening agents. Preferably such minorquantities do not exceed about one-fourth of the total weight of themagnesium oxide or magnesium hydroxide hardening agent. An additionalshortcoming in the use of calcium based oxides is that they caninsolubilize some of the accelerators.

Reactivity and surface area of magnesium oxide (magnesia) differ greatlydepending on the procedure used for manufacture of the magnesia.Lightburned grades of magnesium oxide are calcined at temperaturesranging from about 1600° to 1800° F. Hardburned grades are calcined attemperatures ranging from about 2800° to 3000° F. Deadburned orpericlase grade of magnesium oxide is calcined at temperatures of over4000° F. The lightburned grades are generally available in powder orgranulated form while hardburned grades are available in kiln run,milled, or screened sizes. Periclase is generally available asbriquettes and as screened or milled fractions. There are largedifferences in surface areas for the various magnesias. Thus,lightburned magnesia has a surface area of about 10 to 200 or moresquare meters per gram (m² /g). Hardburned magnesia has a surface areaof about one square meter per gram, whereas deadburned magnesia has asurface area of less than one square meter per gram. Magnesia which isconventionally used as a refractory aggregate is the deadburned orpericlase magnesia. Neither hardburned nor deadburned magnesia areeffective hardening agents. It is the lightburned magnesia which is aneffective hardening agent. Magnesia products having different surfaceareas can be obtained from the Martin Marietta Company under thedesignator of MAGCHEM Magnesium Oxide Products. Illustratively, MAGCHEM30 has a surface area of about 25 square meters per gram. MAGCHEM 50 hasa surface area of about 65 square meters per gram whereas MAGCHEM 200Dhas a surface area of about 170 square meters per gram.

One of the variables for viscosity increase, formation of gel andsubsequent hardening of a phenolic resole resin is dependent on thesurface areas of the lightburned magnesium oxide. Magnesium oxides, withthe higher surface areas, are more active and provide shorter times forgelation and hardening. Thus, lightburned magnesium oxide, having asurface area of less than about 25 square meters per gram, is slowacting and generally will not be used when it is desired to have thebinder composition cure in a relatively short period of time attemperatures below about 120° F. On the other hand, magnesia having ahigher surface area, such as about 65 square meters per gram (m² /g) andabove, will harden the same binder composition in a shorter period oftime. For many applications, using magnesia having a surface area ofabout 25 to 65 square meters per gram is suitable. Hardburned magnesiareacts too slowly as a hardener to be of practical value, and deadburnedmagnesia is sufficiently inert so that it is used conventionally as arefractory with phenolic resin binders with little or no effect on roomtemperature hardening rates.

The phenolic resole resins of this invention contain one or morevolatile solvents, including water. Loss of solvent in the thermallycured compositions leads to increased porosity porosity and permeabilityto liquids and decrease of strength. One means for obtaining the higherstrength and less porosity is to use a larger quantity of lightburnedmagnesium oxide hardener. However, this will further shorten the time ofviscosity build up and gelation. It has now been found that lightburnedmagnesium oxide having at least two different surface areas can providethe improved results such as increased strength without substantiallyaccelerating the viscosity build up. To attain such improved results,the lightburned magnesium oxide hardener comprises particles having atleast two different surface areas with about 25 to 75% thereof by weighthaving a surface area of at least 50 square meters per gram and about 25to 75% thereof, by weight, having a surface area of about 10 to 25square meters per gram. Preferably, the magnesium oxide hardener forsuch improved results consists essentially of particles having at least2 different surface areas as set forth in the previous sentence. Byfollowing this method of using different surface areas, the room orambient temperature gelation can take place in about the same time aswith the higher surface area hardener used alone, even though there issubstantially more of the hardener present but the compressive strengthof the composition on curing is substantially increased and thecomposition has less porosity and less permeability. Furthermore, thefire retardency of compositions having the increased quantity of themagnesia is also improved. Compositions containing the lightburnedmagnesia of different surface areas will optionally contain anaccelerator of this invention, an ester functional hardening agent aswell as fillers, modifiers, aggregate, and other additives at the sameconcentration as with lightburned magnesium oxide which does not containa mixture of the hardener having different surface areas.

The quantity of lightburned magnesium oxide or magnesium hydroxide whichis used in this invention as a hardener is an amount sufficient toincrease the rate of gelation or hardening of the phenolic resole resin.This quantity can vary over a wide range. The quantity of the magnesiumhardener used will vary depending on whether or not an ester hardeningagent is also used in the composition, the surface area of the magnesiumoxide, the specific ester hardening agent, the quantity of magnesium andester hardening agent or agents, the temperature, and the desiredresult. Thus, the magnesium oxide or magnesium hydroxide hardening agentwill generally vary from about 5% to 40% by weight of the resin in thevarious compositions and methods of this invention. However, whenmixtures of lightburned magnesium oxide having different surface areasis used, the quantity of the magnesium oxide preferably varies fromabout 5% to 50% or more by weight of the resin. When magnesium oxide ormagnesium hydroxide hardener is used without the ester hardening agent,it is preferred that from about 10% to 40% by weight be used, based onthe weight of the resin, and particularly 15% to 30% by weight based onthe weight of the resin, and particularly 15% to 30% by weight based onthe weight of resin. When the magnesium oxide or magnesium hydroxide isused together with an ester functional hardening agent, it is preferredthat the quantity of magnesium oxide or magnesium hydroxide hardeningagent vary from about 5% to 30% by weight of the resin, andparticularly, from about 5% to 20%.

The Ester Hardening Agent

The ester functional hardening agent, also referred to as esterfunctional curing agent, accelerates the hardening of the resole whenused with the magnesium hardeners while at the same time use of bothmagnesium hardening agent and ester hardening agent mixed with theresole resin provide a hardening system which is very sensitive to smallquantities of the accelerators of this invention. Mixtures of phenolicresole resins and an ester functional hardening agent in the absence ofmagnesia, or other added alkali, will not harden at 70° F. withinseveral days or longer. The ester functionality for hardening of thephenolic resole resin can be provided by lactones, cyclic organiccarbonates, carboxylic acid esters, or mixtures thereof.

Generally, low molecular weight lactones are suitable as the esterfunctional hardening agent, such as beta or gamma-butyrolactone,gamma-valerolactone, caprolactone, beta-propiolactone,beta-butyrolactone, beta-isobutyrolactone; beta-isopentyllactone,gamma-isopentyllactone, and delta-pentyllactone. Examples of suitablecyclic organic carbonates include, but are not limited to: propylenecarbonate; ethylene glycol carbonate; 1,2-butanediol carbonate;1,3-butanediol carbonate; 1,2-pentanediol carbonate; and 1,3-pentanediolcarbonate.

The carboxylic acid esters which can be used in this invention includephenolic esters and aliphatic esters.

The aliphatic esters are preferably those of short or medium chainlength, e.g., about 1 to 10 carbon mono- or polyhydric, saturated orunsaturated alcohols with short or medium chain length, e.g., about 1 to10 carbon aliphatic, saturated or unsaturated carboxylic acids which canbe mono- or polycarboxylic. The preferred aliphatic esters are those ofalkyl, mono-, di-, or trihydric alcohols with alkyl, or mono-, ordiunsaturated acids which can be mono-, di-, or tricarboxylic. Thecarboxylic acids can be substituted with hydroxy, cyano, chloro, orbromo groups.

As to aromatic esters, such esters can be obtained by esterifying thearomatic, e.g., phenolic, group or groups of a mono- or polyhydricaromatic phenol to prepare a formate or acetate ester of such aromaticcompound. Additionally, the aromatic ester can be an esterified phenoliccompound containing one or more phenolic hydroxyl groups and/or one ormore esterified phenolic hydroxyl groups and further containing one ormore esterified methylol groups positioned ortho and/or para to aphenolic hydroxyl group or esterified phenolic hydroxyl group. Suchphenolic esters and their method of manufacture are disclosed in U.S.Ser. No. 450,989 filed Dec. 15, 1989 entitled "Phenolic ResinCompositions" with P.H.R.B. Lemon et al as inventors which in turn isbased on GB 8829984.7 filed Dec. 22, 1988 with the same inventors andboth the U.S. and British cases are incorporated herein by reference.

It will be understood that the esterified phenolic compound used may bea mono-, a di-or a polyesterified methylolated mono-, di- or polynuclearphenol wherein at least one esterified methylol group is attached to anaromatic ring carbon atom ortho or para to a phenolic hydroxyl group oresterified phenolic hydroxyl group. The acid portion of the phenolicesters can be the same as those of the aliphatic esters.

Specific carboxylic acid esters include but are not limited to: n-butylformate; ethylene glycol diformate; methyl and ethyl lactates;hydroxyethyl acrylate; hydroxyethyl methacrylate; n-butyl acetate;ethylene glycol diacetate; triacetin (glycerol triacetate); diethylfumarate; dimethyl maleate; dimethyl glutarate; dimethyl adipate;2-acetyloxymethyl phenol; 2-methacryloyloxymethyl phenol;2-salicyloyloxymethyl phenol; 2-acetyloxymethyl phenol acetate;2,6-diacetyloxymethyl p-cresol; 2,6-diacetyloxymethyl p-cresol acetate;2,4,6-triacetyloxymethyl phenol; 2,4,6-triacetyloxymethyl phenolacetate; 2,6-diacetyloxymethyl phenol acetate;2,2',6,6'-tetraacetyloxymethyl Bisphenol A; and2,2',6,6'-tetraacetyloxymethyl Bisphenol A diacetate. Also suitable are:cyanoacetates derived from 1 to 5 carbon atom aliphatic alcohols;formates and acetates of benzyl alcohol, alpha,alpha-dihydroxyxylenols,phenol, alkyl substituted phenols, dihydroxybenzenes, bisphenol A,bisphenol F, and low molecular weight resoles. At times, it isadvantageous to use mixtures of the ester functional hardening agents.

Gaseous esters, such as C₁ to C₂ alkyl formates, can be used as esterfunctional hardening agents in low density articles or when applying thebinders to fabric or paper substrates. When gaseous esters are used ashardening agents, the ester is generally not mixed with the resin binderand aggregate but rather is supplied as a gas to the shaped article asis well known in the art.

The ester functional hardening agent is present in an amount sufficientto increase the tensile and compressive strength of the hardenedcomposition. Such quantity also increases the rate of hardening of thephenolic resole resin in the presence of the magnesium hardener and willvary over a broad range such as that of about 5% to 40% by weight of thephenolic resole resin and preferably from about 10% to 25% by weight ofthe resin. As with said magnesium hardening agent, the exact quantitywill depend on the particular ester hardener used, the amount andspecific magnesium hardener used, the temperature at which thecomposition is used or stored, and desired results.

The Phenolic Resole Resin

A broad range of phenolic resole resins may be used in this invention.These can be phenol-formaldehyde resole resins or those wherein phenolis partially or completely substituted by one or more phenolic compoundssuch as cresol, resorcinol, 3,5-xylenol, bisphenol-A, or othersubstituted phenols and the aldehyde portion can be partially or whollyreplaced by acetaldehyde, furaldehyde, or benzaldehyde. The preferredphenolic resole resin is the condensation product of phenol andformaldehyde. Resole resins are thermosetting, i.e., they form aninfusibie three-dimensional polymer upon application of heat and areproduced by the reaction of a phenol and a molar excess of aphenol-reactive aldehyde typically in the presence of an alkali oralkaline earth metal compound as condensing catalyst.

Preferred phenolic resole resins used in this invention have less thanabout 1% and preferably not more than 0.5% by weight of water solublesodium or potassium. Typically, the phenolic resole resin will be aphenol-formaldehyde resin produced by reacting phenol and formaldehydein a molar ratio (phenol: formaldehyde) within the range of from about1:1 to 1:3. A preferred molar ratio for use in this invention rangesfrom about one mole of the phenol for each 1.1 mole of the aldehyde toabout 1 mole of phenol for 2.2 moles of the aldehyde and particularly arange of phenol to aldehyde of 1 to 1.2 to 1 to 2. The phenolic resoleresin will usually be used in solution.

The pH of the phenolic resole resin used in this invention willgenerally vary from about 4.5 to 9.5 with a pH of about 5 to 9 andparticularly about 5 to 8.5 being preferred. Free phenol will typicallybe 2% to about 25% by weight of the resin with preferred levels being 5%to about 12%. The molecular weight of the resin will vary from about 200to 5000 weight average molecular weight with 300 to about 2000 beingpreferred. All other things being equal, higher molecular weights andlower free-phenol will provide shorter gel or hardening time andincrease strength development. The weight average molecular weight (Mw)is measured using gel permeation chromatography and phenolic compoundsand polystyrene standards. The sample molecular weight to be measured isprepared as follows: The resin sample is dissolved in tetrahydrofuranand slightly acidified with 1N hydrochloric or sulfuric acid and driedover anhydrous sodium sulfate. The salts which result are removed byfiltration and the supernatent liquid run through a gel permeationchromatograph.

The resin solids in the resole resin can vary over a broad range, suchas that of about 50% to 90% by weight of the phenolic resole resin.Preferably, the resin solids vary from about 50% to 80% by weight of thephenolic resole resin. The viscosity of the phenolic resole resin, orsimply the resin, can vary over a broad range such as that of about 100to 4,000 cps at 25° C. Preferably, the viscosity varies from about 200to 3,000 cps at 25° C. and particularly from about 250 to 2,000 cps at25° C. The viscosity measurements herein are given in centipoises (cps)as measured by a Brookfield RVF viscometer at 25° C. or by Gardner-Holtviscosities at 25° C. The Gardner-Holt viscosities which are incentistokes are multipled by the specific gravity (generally 1.2) togive the cps at 25° C.

The quantity of resin based on aggregate, when aggregate is used for theraw batch compositions, can vary over a broad range, preferably fromabout 3% to 20% by weight of resin based on the weight of aggregate andparticularly from about 5% to 15% of resin based on the weight ofaggregate.

The liquid portion of the resin is water or water together with anon-reactive solvent. The resin can include a number of optionalmodifiers or additives such as silanes, hexa, or urea. Solvents inaddition to water can be selected from alcohols of one to five carbonatoms, diacetone alcohol, glycols of 2 to 6 carbon atoms, mono- anddimethyl or butyl ethers of glycols, low molecular weight (200-600)polyethylene glycols and methyl ethers thereof, phenolics of 6 to 15carbons, phenoxyethanol, aprotic solvents, e.g., N,N-dimethylformamide,N,N-dimethylacetamide, 2-pyrrolidinone, N-methyl-2-pyrrolidinone,dimethyl sulfoxide, tetramethylene sulfone, hexamethylphosphoramide,tetramethyl urea, methyl ethyl ketone, methyl isobutyl ketone, cyclicethers such as tetrahydrofuran and m-dioxolane, and the like.

Typical water contents for the resins used in this invention will varyfrom about 5% to 20% by weight of the resin and can thus be referred toas aqueous solutions.

Organofunctional silane adhesion promoters are recommended for use whencompositions of this invention include siliceous aggregates, such assilica sands, crushed rock and silicates, and alumina based aggregates.

The organofunctional silanes are used in a quantity sufficient toimprove adhesion between the resin and aggregate. Typical usage levelsof these silanes are 0.1 to 1.5% based on resin weight. Illustrative ofsilanes that are useful are those represented by the generic Formula I.##STR2##

Other useful silanes not represented by Formula I are2-(3,4-epoxycyclohexyl)ethyl trimethoxysilane,bis(trimethoxysilylpropyl)ethylenediamine,N-trimethoxysilylpropyl-N,N,N-trimethylammonium chloride and secondaryamino silane [(RO)₃ Si---CH₂ CH₂ CH₂ ]₂ NH.

The Accelerators

A wide range of materials have been found to be accelerators.Accelerating the hardening of the phenolic resole resin provides for ashorter wait between the time the composition is mixed and when it ishard enough to use. Without the use of an accelerator, in many instancesthe phenolic resole resin, magnesium hardener and optionally esterfunctional hardening agents, with or without fillers or aggregates willharden within 24 hours at 75° F. so that on bending or flexing a sheetor bar of such composition, the sheet or bar will break.

In case of ionizable compounds, it is the anion, e.g., Cl⁻, whichdetermines whether a material is an accelerator. Thus the cation, e.g.,Na⁺, H⁺, Li⁺ does not change the anion from being an accelerator,although it can have some effect on the amount of gelation or hardening.Salts containing the following cations are particularly suitable in theaccelerators of this invention: sodium; potassium; lithium; calcium;magnesium; ammonium; and lower alkyl substituted ammonium compounds suchas those having from 1 to 4 carbon atoms in each alkyl group. Thecations of the previous sentence as well as hydrogen, e.g., such as innitric acid, are the preferred cations for accelerators of thisinvention. However, some compounds which do not appear to ionize arealso accelerators.

The accelerators used in this invention have some solubility in thereaction medium. Such solubility can be different than that in water,particularly when the reaction medium contains substantial quantities ofester and less than about 15% water. For general purposes, however, thesolubility in water of the accelerators is at least 0.1% and preferablyat least 1.0% by weight at 25° C. except for the reactive organic boundchlorine or bromine containing accelerators which are oftensubstantially insoluble in water. The accelerators can be in an acidform, e.g., hydrobromic acid, or in a salt form, as an acid additionsalt of a basic nitrogenous compound or simply in a form which providesthe accelerator anions when mixed with the phenolic magnesium hardenerand optionally the ester. When the acid form is used in the presence ofthe magnesium hardeners, the salt of the acid is formed in situ, e.g.,the magnesium salt when added to a phenolic resole resin and hardenercomposition of this invention, the acid or salt provides the appropriateanion.

The ionizable accelerators, e.g., those which provide chloride,sulfamate, etc. anions to the hardenable mixture appear to increase thesolubility of magnesium or the quantity of soluble magnesium from themagnesium hardener in the hardenable mixture. This in turn acceleratesthe hardening of the phenolic. As stated hereinabove, the acceleratorneeds to have some solubility in the hardenable mixture. In this regard,the choice of the cation for combining with the anion of the ionizableaccelerator needs to be made so that the anion is not renderedinsoluble. This also applies with the use of other materials which mayinsolubilize some of the accelerator anions such as acid addition saltsof amines of the various calcium containing compounds which can be usedtogether with the magnesium hardeners for hardening the phenolic resoleresins. To avoid insolubilization, the accelerator anion needs to be onewhich is not insolubilized by such materials or the hardenable mixtureneeds to contain a high quantity of the accelerator anion so thatsufficient anions remain for solubilizing the magnesium hardener.Illustratively, when calcium is the cation of the accelerator compoundor when calcium containing hardeners are used, the accelerator anionshould be one which forms a water soluble calcium compound such as onehaving a water solubility of at least 1% by weight at 25° C.

In the case of compounds which dissociate in water or alcohols toprovide anions, compounds providing the following anions areaccelerators and appear to be effective by increasing the amount ofmagnesium in the aqueous solution of the magnesium hardener, phenolicresole resin, and other ingredients in the hardenable mixture: chloride,nitrate, sulfate, sulfite, bisulfite, bisulfate, sulfamate, phosphite,hypophosphite, cyanate, bromide, formate, and thiosulfate. Suchaccelerators increase the quantity of soluble magnesium in thehardenable mixture of phenolic, magnesium hardening agent and optionallyester hardening agent or other ingredients without addition of furthermagnesium oxide or magnesium hydroxide. The compound providing the anionaccelerator can be in various forms such as the acid, salt, amine acidaddition salt or reactive organic bound chlorine or bromine containingcompounds. In the case of amine acid addition salts, such salts shouldhave a water solubility of at least 1% by weight at 25° C. By reactiveorganic bound chlorine or bromine containing compounds, we meanmaterials which contain covalently bound chloride or bromide and whichreact by solvolysis or nucleophilic displacement with hydroxyl compoundssuch as water, alcohols, phenolic resins, or amines to liberate chlorideor bromide ions, particularly in the presence of an alkaline materialsuch as magnesium or calcium oxides or hydroxides.

Illustrative of compounds providing the accelerator in the acid formthere can be mentioned: hydrochloric acid, phosphorous acid, hydrobromicacid, formic acid, hypophosphorous acid, sulfamic acid, and sulfuricacid.

Illustrative of salts for providing the anion accelerator, there can bementioned: sodium chloride, lithium carbonate, magnesium bromide,calcium chloride, ammonium sulfate, potassium bromide, potassiumsulfamate, monosodium phosphite, choline formate, and the like.

Lithium carbonate is an accelerator which also improves the strength ofthe hardened resin composition, particularly after thermal cure. Lithiumcarbonate should be avoided when the composition contains water solublecalcium in a quantity greater than the quantity of lithium carbonate,due to possible decomposition of the carbonate by the water solublecalcium, e.g., such as in calcium oxide. Sulfamic acid and salts thereofare accelerators which also increase the strength of room temperaturehardened phenolic resole resin compositions when the resin has at leastabout 10% of free phenol, e.g., 10 to 25% and relatively low molecularweight such as that of a weight average molecular weight (Mw) of about150 to 500.

Illustrative of reactive organic bound chlorine or bromine containingaccelerator compounds, there can be mentioned: cyanuric chloride(2,4,6-trichloro-s-triazine); 2,4-dichloro-6-n-propoxy-s-triazine;2,4-dichloro-6-anilino-s-triazine;2,4-dichloro-6-o-chloroanilino-s-triazine; methanesulfonyl chloride;α,α, α, trichlorotoluene; and 2,3-dibromopropionitrile. Additionalreactive organic bound chlorine or bromine containing compounds include:epichlorohydrin, epibromohydrin, 2,4-dichloro or dibromo-6-substituteds-triazines such as wherein the substituent is alkoxy or aklylamino of1-6 carbons, aryloxy and arylamino of 6-10 carbons, and otherheterocyclic polychlorides, e.g., 2,4-dichloropyrimidine;dichlorodiphenyl silane, silicon chlorides or bromides such as silicontetrachloride, silicon tetrabromide, phenyl trichlorosilane,1,3-dichloro-1,1,3,3-tetramethyl disiloxane; other carbon-chlorine orbromine compounds such as allyl, benzyl and cinnamyl chlorides,1,4-dichloro-2-butene, methyl 2-chloroacetoacetate,1,4-dibromo-2-butene, 2,3-dichloropropionaldehyde,2,3-dichloropropionitrile, α,α¹ -dibromoxylene, α,α¹ -dichloroxylene,2-chloromethyl-m-dioxolane, and acid chlorides, e.g., acetyl chloride,pivaloyl chloride, benzoyl chloride, isophthaloyl chloride,terephthaloyl chloride, and sulfur-chlorine compounds, e.g., benzene andtoluene-sulfonyl chlorides, 1,3-benzene disulfonyl-chloride, andmethanesulfonyl chloride. Additionally, compounds which liberateaccelerator anions or compounds such as hydrogen chloride in water oralkanols such as dichlorophenylphosphine are operable.

Additionally, certain strong basic tertiary amines are accelerators.Illustrative of such accelerators, there can be mentioned1,3,5-tri(lower alkyl) hexahydro-1,3,5-triazines wherein the lower alkylhas from 1 to 3 carbon atoms; 1,4-diazabicyclo[2.2.2.]octane which iscommonly referred to as triethylene diamine; 2,2¹ -bipyridine;1,1,3,3-tetra lower alkyl of 1 to 3 carbon atoms guanidine; 2,4-di(loweralkylaminomethyl)phenol, 2,6-di(lower alkylaminomethyl)phenol, and2,4,6-tris(dilower alkylaminomethyl)phenol wherein each alkyl group hasfrom 1 to 3 carbon atoms; and a compound of the formula: ##STR3##wherein: (i) each of R¹ and R² is a member selected from the groupconsisting of alkyl having 1 to about 3 carbon atoms, and R¹ and R² whentaken together with the nitrogen to which they are attached represent amember selected from the group consisting of piperidino, piperazino,morpholino, thiomorpholino, and pyrrolidino;

(ii) X is a member selected from the group consisting of (--CH2--)_(n)wherein n is an integer of 1 to 6, --CH═CH--CH₂ --, --CH₂ --CH═CH--CH₂,and ##STR4## and (iii) each of R³ and R⁴ is a member selected from thegroup consisting of hydrogen, alkyl of 1 to about 3 carbon atoms, and R³and R⁴ when taken together with the nitrogen to which they are attachedrepresent a member selected from the group consisting of piperazino,morpholino, thiomorpholino, piperidino, and pyrrolidino. Acid additionsalts of the above mentioned basic amino accelerators, wherein the acidincludes one of the previously mentioned accelerator anions, or anotheranion which is not a retarder as well as lithium carbonate, providebeneficial accelerator compounds. Other anions which are not retardersinclude formate, trifluoroacetate, chloroacetate, benzoate,benzenesulfonal and substituted benzoates and substitutedbenzenesulfonates wherein the substituent is alkyl of 1 to 3 carbonatoms, halo, or nitro.

Still another group of accelerators are certain chelating agents, suchas: heptane-2,4-dione; pentane-2,4-dione, also referred to asacetylacetone; 2,2¹ -bipyridine; benzoylacetone; 2-acetylcyclopentanone;and 2-formylcyclopentanone.

The quantity of accelerator used in this invention can vary over a widerange depending on the activity fo the particular accelerator, theamount of acceleration desired, the room or ambient temperature, thesurface area and quantity of the lightburned magnesium oxide, and thetype and quantity of ester hardener. Thus, the quantity of acceleratorsufficient for hastening the gelation and hardening of the phenolicresole resin can vary over a broad range such as that of from about 0.1%to 5% by weight based on the weight of the phenolic resole resin.Preferably, the quantity of accelerator is from about 0.5% to 5% and,particularly, from 1.0% to 5% by weight of the resin. Chlorides can beeffective accelerators by use of as little as 0.1% by weight, based onthe resin but higher quantities of the other accelerators are generallyrequired.

Fillers, Aggregates, and Modifiers

The compositions of this invention can include fillers, modifiers, andaggregates which are conventionally used with phenolic resole resins.The aggregate material may be a particulate material such as that ingranular, powder, or flake form. Suitable aggregate materials includebut are not limited to: magnesite, alumina, zirconia, silica, zirconsand, olivine sand, silicon carbide, silicon nitride, boron nitride,bauxite, quartz, chromite, and corundum. For certain applications, lowdensity aggregate materials such as vermiculite, perlite, and pumice arepreferred. For other applications, preferable high density aggregatesinclude: limestone, quartz, sand, gravel, crushed rock, broken brick,and air cooled blast furnace slag. Sand, gravel, and crushed rock arepreferred aggregates in polymeric concrete. Fillers such as calciumcarbonate, kaolin, mica, wollastonite, and barites can be used inquantities of up to about 50% by weight of the formulated resin product.The quantity of such fillers can equal the quantity of the resin. Hollowmicrospheres of glass, phenolic resin, or ceramic can also be used inquantities of up to about 20% of the formulated resin product. Otheroptional modifiers, particularly in polymer concrete, include fiberssuch as steel, alkali resistant glass, polyester, carbon, siliconcarbide, asbestos, wollastonite fibers, and aromatic polyamides such asKELVAR® aramid fiber which is sold by DuPont, and polypropylene. Thequantity of such fibers can vary over a wide range sufficient to improvethe strength of the composition, e.g., from about 2% to 5% by weight ofaggregate when aggregate is used in the composition.

The raw batch compositions produced by combining the hardenable resinbinder, aggregate, hardening agent or agents, and accelerator mayadditionally comprise any of a number of optional modifiers or additivesincluding non-reactive solvents, silanes, hexamethylenetetraamine,clays, graphite, iron oxide, carbon pitch, silicon dioxide, metalpowders such as aluminum, magnesium, silicon, surfactants, dispersants,air detraining agents, and mixtures thereof. Air detraining agents suchas antifoamers, e.g., dimethylpolysiloxane and the like, can be employedin an amount sufficient to increase the strength of the composition.Such quantities can vary over a broad range such as from about 0.005% to0.1% based on the weight of resin and preferably from about 0.01% to0.05% based on the weight of resin. Illustrative of additional airdetraining agents there can be mentioned: various acetylenic derivativessuch as the SURFYNOLS of Air Products and Chemicals, Inc. such asSURFYNOL DF-110L, SURFYNOL 104, and SURFYNOL GA; and various siloxanessuch as dimethylpolysiloxane and dimethylsiloxane-alkylene oxide blockcopolymer such as PS073 which is supplied by Huls Petrarch Systems.

In foundry applications and sand-binder overlays, or where silica sandis used as the aggregate, a preferred additive is a silane adhesionpromoter, such as gamma-aminopropyl triethoxysilane. In refractoryapplications, clays, metal powders (e.g., aluminum, magnesium, orsilicon), and graphite are preferred additives. When graphite or metalpowders of aluminum, magnesium, or silicon or mixtures thereof are usedas additives, the amount of aggregate, such as alumina or magnesia, canbe reduced to as low as about 70% by weight of the composition.

Applications

The methods and compositions of this invention are particulary usefulin: preparing shaped articles such as bonding refractory aggregate forthe manufacture of bricks and castable monolithic shapes; coatedabrasives; polymer concrete, also referred to as resin-filled aggregate,for repair or protective overlay for concrete to provide resistance toacids, oils, and organic solvents; manufacture of precast shapes such aspipe, tile, wall panel, and the like, where hydrolytic, solvent, acid,and heat resistance are desirable; and impregnated paper for use as autooil and air filters.

Refractory shaped articles include refractory brick and monolithicrefractories. The conventional refractory compositions contain: ahardenable phenolic resole resin; magnesium hardening agent; aggregate;and optionally ester functional hardening agent, metal powders andgraphite. Aggregates normally used for refractories are: magnesia(periclase); alumina; zirconia; silica; silicon carbide; siliconnitride; boron nitride; bauxite; quartz; corundum; zircon sand; olivinesand; and mixtures thereof. Preferred aggregates for refractory use arerefractory magnesia, also referred to as periclase, alumina, and silica.The amount of graphite generally varies from about 5% to 25% by weightof the refractory aggregate and the quantity of metal powder such asaluminum, magnesium, and silicon will generally vary from about 1% to 5%by weight of refractory aggregate. In the case of refractories such asbrick, the refractory composition is pressed into the desired shape andthermally cured or, after pressing, the composition is allowed to hardenat ambient temperature and then thermally cured.

In some refractory applications, prefabricated forms, other thanbrick-like shapes, are required. These "monolithic refractories" arecast by placing a liquid flowable binder-aggregate system into a moldand then filling out the mold by using vibration. Once thebinder-aggregate system room temperature hardens, the mold is strippedaway so that the shape can be thermally cured and readied for use,either before or after transporting the monolithic refractory to itsplace of use.

Hydraulic refractory calcium aluminate cements constitute the currentbinder technology for monolithic refractories. However, chemicalinteraction between molten metal such as iron, steel, and aluminum andhardened cements create problems such as dissolving, softening, orsimply weakening hydrated cement phases which in turn increasepermeability of the hardened refractory shape. This, in turn, severelylimits the service life of the refractory shape. After room temperaturehardening, the monolithic can be thermally cured or carbonized,preferably at the site of use such as part of a furnace lining.Carbonizing takes place at temperatures above 800° C. or 1,000° C.

Polymer concrete is formed by polymerizing a monomer, resin, or mixturethereof in the presence of an aggregate. Polymer concrete had itsinitial application in the repair of Portland Cement concrete. Today,they have many other uses as described herein above. The bindercompositions of this invention are particularly advantageous for thisuse since the lack of high alkalinity and high sodium or potassiumlevels does not affect the aggregate and the composition can cure atroom or ambient temperature in a reasonable time indoors or outdoors.

One use for the compositions of this invention is as coating or toppingapplied to a rigid surface such as concrete. Thus, a room temperaturecurable flooring composition is provided comprising a resin binder andaggregate system prepared as described above. Aggregates for the overlaycoating can be selected from low or high density materials or mixturesthereof. The small amounts of sodium or potassium ions present in thepreferred compositions of this invention from the preparation are notsufficient to produce adverse effects on concrete.

A preferred use for the compostions of this invention are for shapedarticles wherein the article is cast and permitted to harden at room orambient temperatures and is then thermally cured.

In order that those skilled in the art may more fully understand theinvention presented herein, the following procedures and examples areset forth. All parts and percentages in the examples, as well aselsewhere in this specification and claims, are by weight andtemperatures are in degrees Fahrenheit unless otherwise stated.

Procedure For The Preparation And Testing Of Polymer Concrete ForCompressive Strength

A 5-quart Hobart mixer was charged with

990.0 g Industrial Grade Sand No. 4 (Vulcan Materials Co.) This is alsoreferred to herein as coarse sand.

360.0 g Industrial Grade Sand No. 10 (Vulcan Materials Co.) This is alsoreferred to herein as medium particle size sand.

150.0 g Oklahoma Mill Creek Foundry Sand (U.S. Silica) This is alsoreferred to herein as fine sand.

and 22.5 g MAGCHEM 50 (65 square meters per gram) a lightburned magnesiafrom Martin Marietta Magnesia Specialties.

180.0 g of Resin A containing 1.8 g silane, namely 3-glycidoxypropyltrimethoxysilane, was added. The resin-aggregate was mixed for a totalof 2 minutes (at medium setting for 1 minute and high setting for 1minute) then 45.0 g of γ-butyrolacetone and 15.0 g water were added andmixing continued for 1 minute at medium setting and an additional 1minute at a high setting. The mixture was then transferred to a moldcontaining 15 cylindrical cavities of 11/2" depth and 11/2" diameter.Each cavity was lined with thin polyester film to ease removal ofhardened specimens. The charged mold was then vibrated for 2 minutes ata setting of 5.1 using a Syntron Vibrating Table. Surfaces were lightlytroweled and the molds then transferred to a constant temperature (72°F.+/-2° F.) and humidity (51%+/-2%) room. Hardened specimens wereremoved from the mold after 24 hours and either tested or stored forevaluation at a later date. Compressive strengths for polymer concretewere determined on a Tinius Olsen tensile test machine at a slow speedof 0.15 inches/minute. Pounds to failure divided by 1.77 representscompressive strength in psi.

Procedure For The Preparation And Testing Of Polymer Concrete ForTensile Strength

A 5 quart Hobart mixer was charged with 891.0 g Industrial Grade SandNo. 4,324.0 g Industrial Grade Sand No. 10, both from Vulcan MaterialsCo., 135.0 g Oklahoma Mill Creek Foundary Sand (U.S. Silica), and 13.5 gMAGCHEM 50, a lightburned magnesium oxide, (Martin Marietta MagnesiaSpecialties). To this mixture, was added 162.0 g of Resin A containing1.62 g (grams) silane namely 3-glycidoxypropyltrimethoxy silane. Theresin/aggregate mixture was mixed 2 minutes, one at medium speed and oneat high speed. This mixture was then transferred to aluminum forms(pre-sprayed with release agent) and cast to form dogbone specimens 3inches long, 1 inch thick and 1 inch wide at the neck. The sprayed formshad been previously placed on polyester film atop an aluminum tray.Dogbone molds were filled and vibrated for 2 minutes at a setting of 5.1on a Syntron Vibrating Table. The surfaces were lightly troweled andthen the assembly transferred to a constant temperature (72° F.+/- 2°F.) and humidity (51%+/-2%) room and allowed to harden. After 24 hours,samples were removed from molds and either tested or stored forevaluation at a later date. Tensile strengths were determined on aTinius Olsen tensile test machine at a slow speed of 0.15inches/minutes. Readings in psi are indicated on digital readout.

Determination of Soluble Magnesium From Reaction of Resin A & MagnesiaHardener with/without Ester Hardener and with/without Additive

A glass screw cap vial (28×95 mm) was charged with

6.0 g Resin A

0.5 g water

1.5 g γ-butyrolactone (or 2-methoxyethyl ether, as indicated in theExamples or Tables herein),

which was briefly mixed to homogenize the solution whereupon 0.75 glightburned magnesia MAGCHEM 50; Martin Marietta Magnesia Specialties)was added. The mixture was thoroughly mixed for 1 minute using a S/PVortex Mixer (American Scientific Products) at a setting of 9. 1.5 g ofthe uniform dispersion was immediately transferred to a vial containing4.5 g N,N-dimethylformamide (DMF) and 0.5 g methanol. After mixing wellfor 1 minute, the contents were transferred to a centrifuge tube whichwas centrifuged for 5 minutes. The relatively clear liquor was filteredthrough a teflon microfilter. A weighed amount of clear solution wasashed in a platinum dish which was heated at 600° C. in a mufflefurnace. The residue was treated with aqueous hydrochloric acid, dilutedappropriately, and analyzed for magnesium by atomic absorption.

The above freshly mixed solution/magnesia dispersion (1.5 g per vial)was transferred to other empty vials which were placed in 25° C. waterbath. At appropriate times, 4.5 g DMF was added and, after 2 to 3minutes of mixing, complete dispersion of resin was achieved. Then 0.5 gmethanol was added, remixed, and then centrifuged and analyzed asdescribed above. % Magnesium in original sample=% magnesium found×4.27factored to correct for solvent dilution.

Flow Determination of Resin/Hardener/Magnesia/Aggregate Mix

A dome shaped 150 ml glass bowl 3" wide and 2" deep is lightly sprayedwith release agent and charged, in 3 portions, with composite mixderived from resole, ester hardener, lightburned magnesia hardener, andaggregate (silica sands or refractory dead burned magnesias). Thecomposite mix is gently tapped in place with a pestle after eachaddition. The bowl and contents are inverted onto polyester film tapedto a Syntron Vibrating Table. The table is then vibrated for 20 secondsat a setting of 8 (3/4 of maximum setting). The diameter (in inches) ofthe resulting hemisphere is measured and % flow calculated by: ##EQU1##

Procedure For Gel Determination

A screw cap glass vial (28×95 mm) is charged with: 6.0 grams Resin A orResin B (as indicated in the Tables or Examples); additives if any, asindicated in Tables or Examples; 0.5 grams water; and 1.5 grams (g.)gamma butyrolactone. The solution is mixed well prior to addition of0.75 g of lightburned magnesia having a surface area of 65 square metersper gram. The mixture is thoroughly mixed for one minute using a S/PVortex Mixer of American Scientific Products at a setting of 9. Fivegrams (g) of this mixture is immediately transferred to a glass testtube (18×155 mm). A glass rod with a magnetized head fitting isintroduced into the mixture and fitted to a Sunshine Gel Time Meterwhich is then turned on. The tube is immersed in a 25° C. water baththroughout the test.

Determination of gel times with Resin C used 5.0 g of mixture derivedfrom 8.0 g of Resin C, 1.2 g gamma-butyrolactone and 1.6 g of thelightburned magnesia having a surface area of 65 square meters per gram.Solvents were optional. Gel determinations were run at 25° C. or at 60°C. (boiling chloroform).

100° C. gel times with Resin D used 5.0 g of a mixture derived from 8.4g Resin D, 0.0081 ester equivalents of organic hardener, 2-methoxyethylether and 0.16 g of lightburned magnesia having a surface area of 25square meters per g. The weight sum of ester hardener and 2-methoxyethylether was kept constant.

Gel times with resin E used 3.85 g resin and 1.16 g of ethyl lactate or4.0 g Resin E and 1.0 g Triacetin.

Phenolic Resole Properties

Phenolic Resole Resin E is a commercial product sold as Alphaset 9,000by Borden Chemical Company. Resin E is not a resin used in thisinvention except for comparison purposes. This resin has approximately50% aolids, 50% water, a viscosity of 150 cps at 25° C., and pH of 13.

Phenolic Resole Resin A, or simply Resin A, is a phenol formaldehyderesole resin prepared by reacting phenol (P) with 50% formaldehyde (F)at a F/P molar ratio of 1.25 using sodium hydroxide as catalyst and thenfurther formulated. This resin intermediate is formulated with aceticacid, ethanol, methanol, and N,N-dimethylformamide (DMF) to provideResin A which has: a Gardner-Holt viscosity at 25° C., of 2,560Centistokes, or approximately 3,000 cps at 25° C.; 68% solids; 7% freephenol; 10% lower alkyl alcohols; 12% water; 4% DMF; a pH of 5.9, and aweight average molecular weight of 4,000.

Phenolic Resole Resin B, or simply Resin B, is a more alkaline, waterdilutable analog of Resin A without the acetic acid, andN,N-dimethylformamide (DMF), but instead formulated with ethanol toprovide a 7.5% ethanol content and potassium hydroxide 0.75% based onResin B to provide a pH of 8.9 to the final resin solution as well as aweight average molecular weight of 4,000 and 67% solids, 18% water, and7% free phenol, all based on the weight of resin (B.O.R.).

Phenolic Resole Resin C, or simply Resin C, is prepared by reactingphenol (P) with 50% formaldehyde (F) at a F/P molar ratio of 1.25 usingsodium hydroxide catalyst. This resin has a viscosity of 250 cps at 25°C.; 68.6% solids B.O.R.; 15.7% free phenol B.O.R.; 11.7% water B.O.R.; apH of 8.9 and a weight average molecular weight of 290.

Phenolic Resole Resin D, or simply Resin D, is prepared by reactingphenol (P) with 50% formaldehyde (F) at a F/P molar ratio of 2.0 usingpotassium hydroxide catalyst. This resulting intermediate resin has aweight average molecular weight of 390 and is formulated with phenol andDowanol DPnB (dipropylene glycol monobutyl ether-Dow Chemical) to givethe final resin having: solids of 78%; free phenol of 16%; water of 8%;Dowanol DPnB of 8%; potassium of 1.3%; a pH of 9.2; and a viscosity at25° C. of 3450 cps.

EXAMPLE 1

In this example, various additives were tested at 2%, based on resinweight (B.O.R.), unless indicated otherwise, for their effect on therate of hardening of the phenolic resole resin in the presence of bothmagnesium hardener and ester hardener at about 25° C. The rate ofhardening was determined by measuring time of gelation in accordancewith the hereinabove procedure entitled "Procedure For GelDetermination." The resin employed was Resin A, the ester wasγ-butyrolactone, and the magnesium hardener was Magchem 50. The controlfor Table 1 was the composition without additive which gave a gel timeof 48 minutes. Also, for a lower molecular weight analog of Resin A,which is indicated on Table 1 with the superscript "(a)", thecomposition without additive gave a gel time of 67 minutes. Thus, geltimes of less than 48 minutes, wherein the time is not followed by thesupercript "(a)," of the various additives denote accelerators whereasgel times of more than 48 minutes, wherein the time is not followed bythe superscript "(a)," denote retarders. The results of this example areshown in Table 1. Some of the more significant results shown in Table 1are as follows.

The chlorides are the most effective accelerators. Organic chlorine orbromine containing materials that react with water or alcohols at about25 degrees C. at pH of about 5 to 9 to liberate chloride or bromide ionsact as reactive accelerators. Fluoride and bifluoride salts areretarders. Phosphoric acid and salts thereof are effective retarders.Surprisingly, related materials such as phosphorous acid, sodiumphosphite, and hypophosphorous acid are accelerators.

                  TABLE 1                                                         ______________________________________                                        Effect of Additives on Gel Time of Resin A/                                   γ-Butyrolactone/Magnesia Hardener                                       ______________________________________                                        System:                                                                              6.0 g Resin                                                                             1.5 g γ-Butyrolactone                                         A                                                                             0.5 g water                                                                             0.75 Lightburned Magnesia having surface                                      area of 65 square meters per gram                                             (65 m.sup.2 /g)                                              ______________________________________                                             Additive (2% on Resin)                                                   Mix  (Unless otherwise indicated)                                                                     Gel Time, Min. (25° C.)                        ______________________________________                                             Inorganic                                                                1    None               48      67.sup.(a) 62.sup.(a)(b)                      2    Ammonium Bifluoride (0.5%                                                                        148     241.sup.(a)(b)                                     B.O.R.)                                                                  3    Ammonium Chloride  7                                                     4    Ammonium chloride (0.33%                                                                         28                                                         B.O.R.)                                                                  5    Ammonium Fluoride  128                                                   6    Ammonium Nitrate   33                                                    7    Ammonium Phosphate 85                                                         Monobasic                                                                8    Ammonium Sulfate   23                                                    9    Ammonium Sulfite   32                                                    10   Calcium Chloride   19                                                    11   Calcium Formate    45                                                    12   Choline Chloride   25                                                    13   Choline Formate    37                                                    14   Hypophosphorous acid                                                                             40.sup.(a)                                            15   Lithium Carbonate  36                                                    16   Lithium Fluoride   61                                                    17   Lithium Nitrate    17                                                    18   Lithium Sulfate    34                                                    19   Magnesium Chloride 6                                                     20   Magnesium Oxalate  56                                                    21   Magnesium Sulfate  44                                                    22   Meta phosphoric acid/mono                                                                        74                                                         sodium metaphosphate, 1:2                                                23   Phosphoric Acid    107                                                   24   Phosphorous Acid   19                                                    25   Potassium Cyanate  37                                                    26   Potassium Fluoride 126                                                   27   Potassium Iodide   39                                                    28   Potassium Sulfamate                                                                              16                                                    29   Sodium Bromide     30                                                    30   Sodium Carbonate   55                                                    31   Sodium Chloride    12                                                    32   Sodium Bisulfate   36                                                    33   Sodium Bisulfite   26                                                    34   Sodium Dithionite  42                                                    35   Sodium Fluoride    174                                                   36   Sodium Hydroxide (1.4%                                                                           40                                                         B.O.R.)                                                                  37   Sodium Nitrate     29                                                    38   Sodium Nitrite     46                                                    39   Sodium Phosphate, Monobasic                                                                      90                                                    40   Sodium Phosphate, Tribasic                                                                       77                                                    41   Sodium Phosphite, Monobasic                                                                      31                                                    42   Sodium Silicate    47                                                    43   Sodium Sulfate     22                                                    44   Sodium Thiosulfate 20                                                         Organic                                                                  1    Acetic acid        45                                                    2    Acetoguanamine (2,4-di-                                                                          60                                                         amino-6-methyl- .sub.- s-triazine)                                       3    Acetylacetone (pentane-2,4-                                                                      39.sup.(a)                                                 dione at 3% B.O.R.)                                                      4    Aminoacetic acid (glycine)                                                                       65                                                    5    Aminoacetic acid (glycine)                                                                       65                                                    6     -p-Aminobenzoic acid                                                                            108.sup.(a)                                           7    3-Aminopropionic acid                                                                            66                                                         (β-alanine)                                                         8    Aminotri(methylene-                                                                              68                                                         phosphonic acid)                                                         9    Aspartic Acid      104                                                   10   Benzoguanamine (2,4-di-                                                                          49                                                         amino-6-phenyl- .sub.- s-triazine)                                       11   2,3-Butanedione (Biacetyl)                                                                       75.sup.(a)                                            12   Chloroacetamide    52                                                    13   Citric Acid        193                                                   14   2,3-Dibromopropionitrile                                                                         40                                                    15   2,4-Dichloro-6- -n-propoxy- .sub.- s-                                                            22                                                         triazine                                                                 16   2,4-Dichloro-6- -o-chloroanilino-                                                                26                                                          .sub.- s-triazine                                                       17   Dichlorodiphenyl silane                                                                          24                                                    18   α,α-Dichlorotoluene                                                                  46                                                    19   Diethyl phosphite  51                                                    20    -o, -p-Dimethylaminomethyl phenols                                                              59.sup.(a)                                                 DMP-10 of Rohm & Haas Co.                                                21   EDTA               73                                                    22   Guanidine Hydrochloride                                                                          24                                                    23   Glutamic Acid      76                                                    24   Glycolic Acid      47                                                    25   Hexachlorocyclopentadiene                                                                        49                                                    26   Hexamethylenetetraamine                                                                          44                                                    27   1-Hydroxyethylidene-1,1-                                                                         63                                                         diphosphonic acid                                                        28   Imidazole          56                                                    29   Iminodiacetic acid 103                                                   30   Malic Acid         118                                                   31   Malonic Acid       55                                                    32   Melamine           66                                                    33   Methanesulfonyl Chloride                                                                         22                                                    34   Methyl 2,3-dichloropropionate                                                                    43                                                    35    .sub.-- N-methyl imidazole                                                                      48                                                    36   Oxalic Acid        86                                                    37   Phenyltriethoxy silane                                                                           57                                                    38   Succinic acid      41                                                    39   Tartaric Acid      140                                                   40   Terephthalic acid  56                                                    41   Tetraethoxy Silane >276                                                  42   Tetraethoxy Silane 327                                                        (4% B.O.R.)                                                              43   Tetraethoxy Silane 92                                                         (0.5% B.O.R.)                                                            44   Tetraethoxy Silane (40%                                                                          90                                                         hydrolyzed) at 0.5% con-                                                      centration B.O.R. (Silbond 40                                                 of Akzo Chem., Inc.)                                                     45   Tetra  -n-butylammonium chloride                                                                 38                                                    46    .sub.--N, .sub.--N, .sub.--N.sup.1, .sub.--N.sup.1 -tetramethyl-                                40.sup. (a)                                                1,3-propane diamine                                                      47   Alpha, Alpha, Alpha-trichlorotoluene                                                             35                                                    48   Triethylene diamine,                                                                             39                                                         i.e., 1,4-diazabicyclo                                                        [2.2.2]octane                                                            49   Alpha,Alpha,Alpha- 49                                                         trifluorotoluene                                                         50   Trimethyl Borate   46                                                    51   Trimethyl Phosphite                                                                              53                                                    52   2,4,6-Tris(dimethylamino-                                                                        35                                                         methyl)phenol                                                            ______________________________________                                         .sup.(a) Resin having a weight average molecular weight of about 3,000        whereas the resin for the other determinations had a weight average           molecular weight of about 4,000.                                              .sup.(b) 0.75 g lightburned magnesium oxide having a surface area of 10       m.sup.2 /g used in addition to 0.75 g lightburned magnesium oxide having      surface area of 65 m.sup.2 /g.                                           

EXAMPLES 2 AND 3

In these examples, tests were run to determine the effect of lightburnedmagnesia or magnesium hydroxide, esters, and additives on thecompressive strength of polymer concrete. These examples were run inaccordance with the Procedure For The Preparation and Testing of PolymerConcrete set forth hereinbefore.

For the polymer concrete data shown in Table 2 and 3, the compressivestrengths were determined, unless specified otherwise, on roomtemperature (R.T.) cured specimens using Resin A, γ-butyrolactone asester, lightburned magnesia or magnesium hydroxide as the alkali, andmixture of silica sands as aggregate.

It can be seen in Table 2 and Table 3 that:

(a) Fluoride retarder lowers R.T. strength after 24 hours, but thisrelative effect is more dramatic after 8 hours when compared to control.Lithium carbonate and calcium formate increase 1 day R.T. strength, butlithium fluoride (very low solubility) has no effect.

(b) Replacement of magnesia by a chemical equivalent of magnesiumhydroxide leads to a dramatic decrease in compressive strength. However,magnesium hydroxide responds to accelerative and retardative effects.Chloride increases 24-hour R.T. compressive strength whereas fluoridedecreases strength.

(c) Replacement of γ-butyrolactone ester by an equal weight of inerthigh boiling solvent (a glycol diether) leads to a dramatic reduction in3 and 7 day R.T. strength. Four day immersion in 10% acetic acid, aftera 3 day dry R.T. cure, leads to a strength decrease relative to a 7-daydry R.T. cure. With butyrolactone, an increase in strength is seen afterthe acetic acid treatment.

(d) Four day hot (90° C.) water immersion preceded by 3 day dry R.T.cure of concretes prepared using γ-butyrolactone and lightburnedmagnesia leads to significantly higher strength than systems where inertsolvent replaces ester or where magnesium hydroxide replaces magnesia.

(e) Sulfamates which are good accelerators show a negative effect onstrength (8 or 24 hours) with Resin A. However, sulfamates show improvedstrength with low molecular weight resins and high free phenol contents,e.g., 10% to about 25% of free phenol based on the weight of resin, ascan be seen in Example and Table 10 herein. Moderate accelerator Li₂ CO₃shows a 24% strength increase after 24 hours.

                                      TABLE 2                                     __________________________________________________________________________    Polymer Concrete Using Resin "A" Effect of Alkali and Ester                   __________________________________________________________________________    Mix:   36 g. Resin per 300 g. sand mixture                                           Diglyme or γ-Butyrolactone (25% B.O.R.)                                 Water (8.3% on resin)                                                         Alkali source (magnesia or magnesium hydroxide (hardener)                     Epoxy Silane, 3-glycidoxypropyltrimethoxy silane,                             (1% on resin)                                                          __________________________________________________________________________                 Compressive Strength, psi (Average of 3)                                      3 Days R.T. Dry + 4 Days Wet Immersion                                        3 Days                                                                             7 Days                                                                   R.T. R.T.                                                                              H2O/ H2O/                                                                              10% Acetic                                       Mix        Dry  Dry R.T. 90° C.                                                                     Acid R.T.                                      __________________________________________________________________________      Diglyme.sup.(a)                                                                          437   777                                                                               669 3423                                                                               611                                             (25% on resin)                                                                Lightburned Magnesia                                                          of 65 m.sup.2 /g                                                              (12.5% on resin)                                                              γ-Butyrolactone                                                                    2962 3704                                                                              3546 4893                                                                              3934                                             (25% on resin)                                                                Lightburned Magnesia                                                          of 65 m.sup.2 /g                                                              (12.5% on resin)                                                              γ-Butyrolactone                                                                    587  1628                                                                              1601 3245                                                                              1628                                             (25% on resin)                                                                Magnesium Hydroxide                                                           (18% on resin).sup.(b)                                                      __________________________________________________________________________     .sup.(a) Diglyme = (2methoxyethyl)ether, inert solvent                        .sup.(b) Equivalent to 12.5% Lightburned Magnesia Oxide                      Effect of Additives on Compressive Strength Using γ-Butyrolactone       (Ester)                                                                       With Magnesium Hydroxide as Alkali Hardener                                   Additive (% on Resin)                                                                       24 Hr. R.T. Comp. Str., psi (average of 3)                      __________________________________________________________________________    None          167                                                             NH.sub.4 Cl (2% B.O.R.)                                                                     214                                                             NH.sub.4 F (2% B.O.R.)                                                                      47                                                              __________________________________________________________________________

                  TABLE 3                                                         ______________________________________                                        Polymer Concrete Using Resin A -                                              Effect of Additives on Compressive Strength                                   ______________________________________                                        Mix: Resin A (36 g per 300 g sands)                                                                        Aggregate:                                            γ-Butyrolactone (25% B.O.R.)                                                                    Mixture of 3                                                                  sands:                                                Magchem 50 (12.5% B.O.R.) (MgO)                                               Water (8.3% B.O.R.)     198 g coarse                                          Epoxy silane, namely, 3-glycidoxypropyl-                                                              72 g medium                                           trimethoxy silane (1% B.O.R.)                                                                         30 g fine                                        ______________________________________                                                          Room Temp. Comp. Str.,                                                        psi (average of 3)                                          Additive            8 Hrs.     24 Hrs.                                        (% of resin)        Hardening  Hardening                                      ______________________________________                                        None (control)      477                                                       NaF (at 2% B.O.R.)  168                                                       Sodium Sulfamate (at 2% on Resin)                                                                 393                                                       Control                        1390                                           NaF (at 2% B.O.R.)             1103                                           Sodium Sulfamate (at 1% B.O.R.)                                                                              1110                                           Control                        1353                                           Li.sub.2 CO.sub.3 (at 2% B.O.R.)                                                                             1781                                           LiF (at 2% B.O.R.)             1315                                           Calcium Formate (at 2% B.O.R.) 1520                                           ______________________________________                                    

In addition to the above Table 3, deadburned pulverized periclase wasused by substituting about 18% of the periclase in place of the 12.5%MAGCHEM 50 magnesium oxide in the mix of Table 3. Without a retarder,the mix with periclase showed a 24-hour compressive strength, psi of105, and with a 2% addition of ammonium fluoride, the mix remained softafter 5 days at room temperature. The periclase was 98.1% MgO on anignited basis with a bulk specific gravity of 3.28 having 95% passingthrough a 50 U.S. Sieve Series screen and 75% passing a 200 U.S. SieveSeries screen.

EXAMPLE 4

In this example, tests were run to determine the effect of surface areaof the lightburned magnesia hardener on gel time. The compositionstested were 6.0 g (grams) Resin A; 0.5 g water; 1.5 g of γ-butyrolactoneand 0.75 g of magnesia hardener of different surface areas. The resultsare shown in Table 4. It can be seen from Table 4 that gel time is afunction of magnesia surface area and concentration with the highersurface areas or concentrations decreasing the gel time.

                  TABLE 4                                                         ______________________________________                                        Effect of Magnesia on Gel Time of Resole-                                     Ester-Magnesia Hardener                                                       ______________________________________                                        System: 6.0 g Resin A                                                                              1.6 g γ-Butyrolactone                                      0.5 g water  0.75 g (grams) Lightburned                                                    Magnesia (MgO)                                           ______________________________________                                             Surface Area of MgO, m.sup.2 /g                                          Mix  (square meters per gram)                                                                         Gel Time, Min. at 25° C.                       ______________________________________                                        1    100                26                                                    2    65                 50                                                    3.sup.(a)                                                                          65                 99                                                    4    25                 119                                                   ______________________________________                                         .sup.(a) 1/2 quantity of MgO used.                                       

EXAMPLE 5

This example was performed to show the effect of additives which werepreviously shown to be accelerators or retarders at the 25° C. roomtemperature (R.T.) hardening on the solubilization of magnesium in thereaction mixture. The example was run in accordance with the "ProcedureFor Determination of Soluble Magnesium From Reaction Of Resin A &Magnesia Hardener With/Without Ester Hardener And With/Without Additive"which is set forth hereinabove. The results are shown in Table 5. Thepercentage readings of B.O.R. following the additive are percentages ofthe additive based on resin weight (B.O.R.). It can be seen from Table 5that chloride increases magnesium solubilization and fluoride decreasessolubilization in the reaction mixture. A similar effect is seen withoutester in mixes 4-6 wherein the ester is replaced by inert solvent2-methoxyethyl ether. The chelating agent, pentane-2,4-dione alsoincrease magnesium solubilization.

                  TABLE 5                                                         ______________________________________                                        Effect of Additives on Solubilization of Magnesium                            ______________________________________                                        System: Resin A                6.0    g                                               γ-Butyrolactone (or inert solvent)                                                             1.5    g                                               Water                  0.5    g                                               Lightburned Magnesia (65 m.sup.2 /g)                                                                 0.75   g                                       ______________________________________                                                        % Soluble Magnesium                                                           Reaction Time, Min.                                           Mix.sup.(a)                                                                         Additive (% on Resin)                                                                         1       12   60                                         ______________________________________                                        1     None            0.48    0.80 1.60 (50 min)                              2     Sodium chloride 0.53    0.97 --                                               (2% B.O.R.)                                                             3     Ammonium fluoride                                                                             0.26    0.53 0.69                                             (0.17% B.O.R.)                                                          4     None            0.43    0.76 --                                         5     Sodium chloride 0.52    0.91 --                                               (2% B.O.R.)                                                             6     Ammonium fluoride                                                                             0.20    0.34 --                                               (0.17% B.O.R.)                                                          7.sup.(b)                                                                           None            0.0015  --   --                                         8     Citric Acid (2% B.O.R.)                                                                       0.16    0.31                                            9     Tetraethoxy Silane                                                                            0.47    0.72                                                  (2% B.O.R.)                                                             10.sup.(c)                                                                          Tetraethoxy Silane                                                                            0.43    0.69                                                  (2% B.O.R.)                                                             11.sup.(d)                                                                          Silbond 40      0.54    0.90 1.25                                                       (after 15 min.)                                               12     .sub.--N, .sub.--N, .sub.--N.sup.1, .sub.--N.sup.1 -Tetramethyl-                             0.64    1.05                                                  1,3-propane-diamine                                                           (2% B.O.R.)                                                             13    Pentane-2,4-dione                                                                             0.73    1.09 1.67                                             (2% B.O.R.)                                                             ______________________________________                                         .sup.(a) Mixes 1-3, 7-13 use butyrolactone                                    Mixes 4-6 use inert solvent 2methoxyethyl ether                               .sup.(b) No resin is present; but proportionate amounts of water,             alcohols, D.M.F. in resin are present.                                        .sup.(c) Delayed addition of ester and magnesia by five minutes.              .sup.(d) Delayed addition of ester and magnesia by 30 minutes.           

EXAMPLE 6

In this example, a number of di- and tri-amino compounds were tested asaccelerators, including acyclic and cyclic compounds. The results ofthis example are shown in Table 6. Mix No. 8 shows the additiveaccelerating effect of TRIS and a chloride.

                                      TABLE 6                                     __________________________________________________________________________    Effect of Solvent & Amine on Gel Time of Resin C/γ-Butyrolactone/Mag    nesia                                                                         __________________________________________________________________________    Mix:         8.0 g Resin C                                                                 1.33 g solvent                                                                1.2 g γ-butyrolactone                                                   1.6 g magnesia (surface area of 65 m.sup.2 /g)                   __________________________________________________________________________                        Amine           Gel Time                                  Mix                                                                              Solvent          (2% on resin)   Min. (25° C.)                      __________________________________________________________________________    1  H.sub.2 O        --              210                                       2  1:1 H.sub.2 O/dipropylene glycol                                                               --              315                                           -n-monobutyl ether (DP.sub.n B)                                           3  1:1 H.sub.2 O/DP.sub.N B                                                                       TRIS {2,4,6-tris(dimethyl-                                                                    205                                                           aminomethyl)phenol}                                       4  1:1 H.sub.2 O/DP.sub.n B                                                                       1,1,3,3-tetramethyl-guanidine                                                                 277                                       5  1:1 H.sub.2 O/DP.sub.n B                                                                        .sub.--N, .sub.--N, .sub.--N.sup.1, .sub.--N.sup.1                           -tetramethyl-   194                                                           ethylene diamine                                          6  1:1 H.sub.2 O/DP.sub.n B                                                                        .sub.--N, .sub.--N, .sub.--N.sup.1, .sub.--N.sup.1                           -tetramethyl-   174                                                           1,3-propanediamine                                        7  1:1 H.sub.2 O/DP.sub.n B                                                                       1,3,5-triethyl hexahydro-                                                                     213                                                           1,3,5- .sub.- s-triazine                                  8  1:1 H.sub.2 O/DP.sub.n B                                                                       TRIS + 0.5% HCl, which                                                                        168                                                           corresponds to TRIS                                                           dihydrochloride                                           9  1:1 H.sub.2 O/DP.sub.n B                                                                       0.5% HCl        244                                       10 1:1 H.sub.2 O/tetramethylene-sulfone                                                           TRIS            217                                       11 1:1 H.sub.2 O/polyethylene glycol                                                              TRIS            195                                          (mol. wgt. 300)                                                            12 1:1 H.sub.2 O/polyethylene glycol mono-                                                        TRIS            185                                          methyl ether (mol. wgt. 350)                                               13 1:1 H.sub.2 O/polyethylene glycol mono-                                                        --              275                                          methyl ether (mol. wgt. 350)                                               14 1:1 H.sub.2 O/DP.sub.n B                                                                        .sub.--N, .sub.--N, .sub.--N.sup.1, .sub.--N.sup.1                           -tetramethyl    106                                                           diaminomethane                                            15 1:1 H.sub.2 O/DP.sub.n B                                                                        .sub.--N, .sub.--N-diethylethylenediamine                                                    189                                                                              (164)*                                 16 1:1 H.sub.2 O/DP.sub.n B                                                                        .sub.--N, .sub.--N-dimethyl-1,3-propanediamine                                               185                                       17 1:1 H.sub.2 O/DP.sub.n B                                                                        .sub.--N, .sub.--N-dipiperidinylmethane                                                      164                                       18 1:1 H.sub.2 O/DP.sub.n B                                                                        .sub.-- N-(3-aminopropyl)morpholine                                                          159                                       19 1:1 H.sub.2 O/DP.sub.n B                                                                       4-amino-2,6-dimethylpyrimidine                                                                251                                       20 1:1 H.sub.2 O/DP.sub.n B                                                                       2.2.sup.1 -bipyridine                                                                         206                                       __________________________________________________________________________     *Prereacted amine with resin prior to addition of ester and MgO.         

EXAMPLE 7

Tests were performed to show the effect on gel time of various additiveswith certain esters. The gel time tests were run in accordance with theprocedure set forth hereinbefore entitled "Procedure For GelDetermination." The test results set forth in Table 7 show acceleratoror retarder activity of various additives at different temperatures andwith different esters and resins.

                                      TABLE 7                                     __________________________________________________________________________    Effect of Additives on Gel Time of Resole-Ester-Magnesia Hardener                                Additive (2% on                                                                           Temp Gel Time,                                 Mix.sup.(a)                                                                       Resin                                                                             Ester      Undiluted Resin)                                                                          °C.                                                                         Minutes                                   __________________________________________________________________________    1   A   γ-Butyrolactone                                                                    None        60   7                                         2   A   γ-Butyrolactone                                                                    Sodium fluoride                                                                           60   21                                        3   A   γ-Butyrolactone                                                                    Monosodium phosphate                                                                      60   13                                        4   A   Methyl lactate                                                                           None        25   92                                        5   A   Methyl lactate                                                                           Ammonium chloride                                                                         25   22                                        6   B   γ-Butyrolactone                                                                    None        25   48                                        7   B   γ-Butyrolactone                                                                    Ammonium chloride                                                                         25   19                                        8   B   γ-Butyrolactone                                                                    Ammonium fluoride                                                                         25   267                                       9   B   γ-Butyrolactone                                                                    None        25   52                                        10  B   γ-Butyrolactone                                                                    Sodium sulfate                                                                            25   12                                        11  A   Propylene carbonate                                                                      None        25   23                                        12  A   Dimethyl succinate                                                                       None        25   71                                        13  A   Dimethyl succinate                                                                       Lithium chloride                                                                          25   13                                        __________________________________________________________________________     .sup.(a) 6.0 g resin, 0.5 g water 1.5 butyrolactone, 0.75 g lightburned       magnesia (65 m.sup.2 /g surface area) for Mixes 1-3, 6-8. Additional 1.8      water for Mixes 9-10 in relation to Mix 1. Replace butyrolactone by 1.75      methyl lactate for mixes 4-5 in relation to Mix 1. In mixes 11-13, used       the indicated ester in place of butyrolactone in relation to Mix 1.      

EXAMPLE 8

This example was performed to determine the effect of magnesia/limeratios and additives on gel times of a resole and ester. The results ofthis example are shown in Table 7. It can be seen that in Resin A, up to33% of MgO hardener can be replaced by CaO with substantially no effecton gel time (mixes 1-4) but a problem results at a 1:1 ratio (mix 5). Incontrast, Resin C (lower molecular weight and higher free phenol) cannottolerate even a 20% replacement of MgO with CaO without significantlyadversely affecting gel time (Mix 10 versus control Mix 8). Theseresults run counter to the Gupta U.S. Pat. No. 4,794,051 patent citedearlier herein in Col 4, lines 45-53 and 34-37, it is stated thatmagnesium oxide or hydroxide is too slow a hardening agent and that itis preferable to use a mixture of calcium and magnesium alkalis at aratio of 10:1 to 0.1 to 10. Furthermore, it should be pointed out thatthe Gupta compositions remain thermoplastic "at about 20° C. to 70° C.for 24 to 100 hours or longer" (Col. 60, line 23 of Gupta) whereas themixtures of phenolic resole resin and hardener or hardeners of thisinvention without retarder, harden in less than 24 hours.

                                      TABLE 8                                     __________________________________________________________________________    Effect of Magnesia Hardener Lime Ratio and Additives On Gel Time of           Resole-Ester                                                                                  Temp.                                                                              Gel Time,   Additive                                     Mix.sup.(a)                                                                       Resin                                                                             Alkali.sup.(b)                                                                        °C.                                                                         Minutes     (2% on Resin)                                __________________________________________________________________________    1   A   MgO     25   48          --                                           2   A   4:1 MgO/CaO                                                                           25   49          --                                           3   A   3:1 MgO/CaO                                                                           25   50          --                                           4   A   2:1 MgO/CaO                                                                           25   52          --                                           5   A   1:1 MgO/CaO                                                                           25   Mix lumps, test not run                                                                   --                                           6   A   2:1 MgO/CaO                                                                           25   11          NH.sub.4 Cl                                  7   A   2:1 MgO/CaO                                                                           25   104         NH.sub.4 F                                   8   C   MgO     60   54          --                                           9.sup.(b)                                                                         C   2:1 MgO/CaO                                                                           60   123         --                                           10.sup.(b)                                                                        C   4:1 MgO/CaO                                                                           60   94          --                                           11  C   MgO     60   62          Melamine                                     12  C   MgO     60   79          Aspartic acid                                13  C   MgO     60   28          --                                           14  C   MgO     60   42          NH.sub.4 F (0.15% on resin)                  15.sup.(c)                                                                        C   MgO     60   47          --                                           16.sup.(c)                                                                        C   MgO     60   63          NH.sub.4 F (0.15% on resin)                  17.sup.(c)                                                                        C   MgO     60   115         Tetraethoxysilane                            18.sup.(c)                                                                        C   MgO     60   86          Tetraethoxysilane                                                             (1.0% on resin)                              __________________________________________________________________________     .sup.(a) For 6 g Resin A use 0.5 g water, 1.5 g butyrolactone, 0.75 g         alkali (lightburned MgO with surface area of 65 m2/g). For 8 g Resin C us     1.2 g butyrolactone in Mixes 13-14, no ester in mixes 8-12 and 15-18, and     1.6 g alkali, namely the MgO, CaO or mixtures thereof in all mixes with       Resin C.                                                                      .sup.(b) Mild exotherm upon addition of alkali, coalescing of particles       observed.                                                                     .sup.(c) Resin stored at about 40° F. for several months.         

EXAMPLE 9

This example was performed to show the effect of additives on gel timesof Resin E which is a highly alkaline phenolic resole resin having a pHof about 13. The compositions of this example did not contain amagnesium hardening agent. The results of this example are shown inTable 9. Normally, with Resin E, the ethyl lactate induces hardening ofthe resin as shown by the gelation of Mix 1. However, all of theadditives, including the chloride, which is an accelerator with themagnesium hardeners, acted as accelerators or had no effect.

                  TABLE 9                                                         ______________________________________                                        Effect of Additives on Gel Time OF Resin E with Ester                         Hardener (Resin E = Alphaset 9000 of Borden Chemical Co.)                          Additive                     Gel Time                                    Mix  2% on Resin       Ester      (25° C./Min)                         ______________________________________                                        1    None              Ethyl Lactate                                                                            46                                          2    Sodium chloride   Ethyl Lactate                                                                            49                                          3    Sodium sulfate    Ethyl Lactate                                                                            49                                          4    None              Triacetin  11                                          5    Ammonium chloride Triacetin  13                                          6    Ammonium bifluoride                                                                             Triacetin  13                                          7    Ammonium sulfamate                                                                              Triacetin  13                                          8    Sodium phosphate monobasic                                                                      Triacetin  16                                          9    Sodium fluoride   Triacetin  13                                          10   Sodium sulfite    Triacetin  15                                          11   Formic acid (1.5% B.O.R.).sup.(a)                                                               Triacetin  13                                          ______________________________________                                         .sup.(a) Acid equivalent to 2% sodium phosphate monobasic.               

EXAMPLE 10

This example shows a series of experiments (Exp.) wherein increasedtensile strength is obtained in a composition containing certainaccelerators in relation to the same composition without an accelerator.

The results of this example are shown in Table 10.

The composition of Example 10 consisted of: (a) refractory magnesiaaggregate made up predominantly of particles having a sieve size of 14to 48; (b) 10% of Resin F, based on the weight of aggregate; (c) 15% ofgamma-butyrolactone, based on the weight of Resin F (B.O.R.); and (d)30% of MAGOX 98 Premium, based on the weight of Resin F, said MAGOX 98Premium being a lightburned magnesium oxide hardening agent having asurface area of 100 square meters per gram which is sold by PremierRefractories & Chemicals, Inc. The quantity of accelerator, whenemployed, was at a level of 1%, based on the weight of resin (B.O.R.).The tensile strength readings provided in Table 10 for this example arethat of an average of 3 specimens with the parenthetical valuerepresenting the median.

Resin F is a phenol-formaldehyde resole resin having the followingproperties: solids of 64.12%, based on the weight of resin; a watercontent of 5.65%, based on the weight of resin; a free phenol content of25.19%, based on the weight of resin; a number average molecular weight(Mn) of 107; a weight average molecular weight (Mw) of about 200; aviscosity at 25° C. of M 1/4 on the Gardner-Holt scale or 325centistokes, which is converted to about 390 centipoise. In themanufacture of Resin F, there is charged to a reactor a molar ratio offormaldehyde to phenol of 0.93 which is reacted under mild heatingconditions so that 25.2% by weight of the phenol remains unreacted inthe resin after distillation to reduce water to about 6% and thus alsoraises the molar ratio of formaldehyde reacted with phenol to a ratio ofgreater than one, in spite of the fact that the molar ratio offormaldehyde to phenol charged to the reactor is less than one.

The resin bonded magnesia refractory tensile specimens were prepared andtested as follows. Resin F and the magnesium hardening agent wereintimately admixed with the refractory magnesia. The accelerator, whenused, was added at this stage. Following this stage, thegamma-butyrolactone was added to the mixture and the mixture was furthermixed for a period of about 3 or 4 minutes. A 150 gram sample of the mixwas then charged to a dogbone die which was then subjected to a rammingpressure of 15 tons for one minute to produce a tensile strengthspecimen. The specimens, 3 inches long, 1 inch thick, and 1 inch wide atthe neck, were allowed to stand 24 hours (H.) at constant temperatureand humidity (R.T.) of 72° F. +/-2° F. and 51% +/-2% relative humidityprior to being subjected to breaking on a Tinius Olsen tensile testmachine. Some of the dogbone specimens, after the 24 hour (H.) period atthe constant temperature and humidity conditions (R.T.) were subjectedto a thermal treatment of 110° C. for 2 hours and then allowed to coolto room temperature prior to breaking.

It can be seen from Table 10 that: the addition of the sulfamateaccelerator increased the room temperature tensile in relation to thesame composition without the sulfamate additive; and that the additionof lithium carbonate increased both the room temperature and thermalcure tensile in relation to the same composition without this additive.

                  TABLE 10                                                        ______________________________________                                        Effect Of Certain Accelerators On Tensile Strength of Aggregate               Bound With Low Molecular Weight Phenolic Resole Resin with                    Magnesium Oxide Hardener and Ester Hardener                                                   Tensile Strength, psi                                                                          24 H. at R.T. +                              Exp.  Additive        24 H. at R.T.                                                                            2 H. at 110° C.                       ______________________________________                                        1     None            55     (55)  857   (890)                                2     Sodium Sulfamate                                                                              183    (175) 952   (985)                                      (1% B.O.R.)                                                             3     Lithium Carbonate                                                                             135    (140) 1035  (1060)                                     (1% B.O.R.)                                                             4     Ammonium Sulfamate                                                                            132    (140) 717   (770)                                      (1% B.O.R.)                                                             ______________________________________                                    

EXAMPLE 11

In this example, compressive strength tests were made at different timeson a polymer concrete composition in comparison with the samecomposition which also contained 2%, based on the weight of Resin A(B.O.R.), of the accelerator N,N,N¹,N¹ -tetramethyl-1,3-propanediamineand additionally, in some instances 0.1%, based on the weight of resin(B.O.R.) of SAG 10, a defoamer which also acts as an air detrainingagent. SAG 10 is a 10% emulsion of dimethylpolysiloxane which is sold byUnion Carbide Corporation.

The compressive strength tests of this Example 11 as well as the basiccomposition or standard mix is that set forth previously herein in theprocedure entitled "Procedure For The Preparation And Testing of PolymerConcrete For Compressive Strength." The results of this example are setforth in Table 11.

It can be seen from Table 11 that the compressive strength of thestandard mix or control at room temperatures (R.T.) was less than thatof the standard mix after the inclusion of the accelerator at 2%, basedon the weight of resin (B.O.R.), which in turn was less than that of thestandard mix plus accelerator at 2% (B.O.R.) and 0.1% (B.O.R.) of theair detraining agent. Table 11 also shows that the compressive strengthof the standard mix when the accelerator and the air detraining agentwere included in the composition was greater than that of the standardmix plus the accelerator under the one day of hardening age roomtemperature plus 2 hours thermal cure at 100° C.

                                      TABLE 11                                    __________________________________________________________________________    Compressive Strength of Polymer Concrete with Accelerator                     And Air Detraining Agent                                                                    Compressive Strength, psi                                                                     Standard Mix +                                                Standard Mix                                                                         Standard Mix +                                                                         Accelerator + Air                               Cure Conditions                                                                             (Control)                                                                            Accelerator                                                                            Detraining Agent                                __________________________________________________________________________    8 Hours at Room Temp.                                                                        379    511      664                                                           387    534      658                                                           379    494      678                                            (Average)      (382)  (513)    (667)                                          One Day at Room Temp.                                                                       1246   1551     1729                                                          1291   1686     1777                                                          1257   1559     1876                                            (Average)     (1265) (1559)   (1794)                                          One Day at Room Temp. +                                                                            5607     7153                                            Two Hours at 100° C.                                                                        5777     6664                                                                 5294     7110                                            (Average)            (5559)   (6976)                                          __________________________________________________________________________

EXAMPLE 12

This example shows gel times of Resin A in accordance with the procedureand composition, also referred to as standard or control composition,set forth hereinbefore entitled "Procedure For Gel Determination."

The results of this example are set forth in Table 12. Experiment (Exp.)1 in Table 12 is the standard composition set forth in theabove-mentioned procedure and consists of: 6 g of Resin A; 0.5 g ofwater; 1.5 g of gamma-butyrolactone; and 0.75 g of lightburned magnesiumoxide hardener having a surface area of 65 square meters per gram (MgO50).

Exp. 2 in Table 12 shows the decrease in the time required for gelationof the standard composition by addition of 2% B.O.R. of the hardeningaccelerator N,N,N¹,N¹ -tetramethyl-1,3-propanediamine.

Exp. 3 in Table 12 shows the prolongation of the time required to gelthe composition of Exp. 2 when the ester hardening agent, namelygamma-butyrolactone, is replaced with an inert solvent.

Exp. 4 in Table 12 shows that the addition of a relatively low surfacearea lightburned magnesium oxide hardener, namely Magchem 20M, hadlittle effect on further shortening the time required for gel formationof the composition in Exp. 2 which contains both the gamma-butyrolactoneand the lightburned magnesium oxide hardener having a surface area of 65square meters per gram. Magchem 20M has a surface area of ten squaremeters per gram.

Exp. 5 in Table 12 shows that the addition of the relatively low surfacearea (10 square meters per gram) lightburned magnesium oxide hardeningagent (Magchem 20M) had a relatively small effect on decreasing the timeit takes to gel the composition of Exp. 3.

                  TABLE 12                                                        ______________________________________                                        Effect On Gel Times Of Resole Resin A By Gamma-Butyrol-                       actone Hardener, Various Lightburned Magnesium Oxide                          Hardening Agents And  .sub.--N, .sub.--N, .sub.--N.sup.1, .sub.--N.sup.1      -Tetramethyl-1,3-                                                             Propanediamine Accelerator at 25° C.                                                               Time                                              Composition                 (Minutes)                                         ______________________________________                                        Exp. 1                                                                              Control (Resin A/H2O/γ-Butyrol-                                                                   64                                                  actone/MgO 50) (No accelerator)                                         Exp. 2                                                                              Control + 2%  .sub.--N, .sub.--N, .sub.--N.sup.1, .sub.--N.sup.1              -tetramethyl-1,3-         48                                                  propanediamine (B.O.R.) Accelerator                                     Exp. 3                                                                              The Composition of Exp. 2 but replace γ-                                                          115                                                 Butyrolactone with 2-methoxyethyl                                             ether (inert solvent)                                                   Exp. 4                                                                              The Composition of Exp. 2 but with addition                                                             46                                                  of 0.75 grams (g) Magchem 20M for each                                        6 g of Resin A                                                          Exp. 5                                                                              The Composition of Exp. 3 but add                                                                       94                                                  0.75 g Magchem 20M per each 6 g of Resin A                              ______________________________________                                    

EXAMPLE 13

The compositions of this example are the same as those of Example 12except for the presence or absence of magnesium or ester hardeningagents and together with Example 12 and Table 12 and the following Table13 serve to show the synergism obtained by using both a magnesiumhardening agent and an ester hardening agent in the presence of anaccelerator. Thus, in Exp. 2 of Table 12, it took only 48 minutes forthe composition containing the accelerator and both an ester and themagnesium hardening agent to gel. Exp. 3 of Table 12, which is identicalto Exp. 2 of the same table except that it does not contain the esterhardening agent, took 115 minutes to gel. It can be seen from Table 13that the identical composition of Exp. 2 in Table 12 but without themagnesium hardener had not gelled after 14 days. Table 13 also showsthat the accelerator without the magnesium hardener or ester hardenerhad little, if any, effect on the viscosity increase of Resin A inrelation to my use of the accelerator together with ester and magnesiumhardener.

                  TABLE 13                                                        ______________________________________                                        Effect Of Ester Hardener And Accelerator On Viscosity at 25° C.        Of Resin A Over Period Of Time                                                ______________________________________                                        Hours at                                                                             6 g Resin A      6 g Resin A                                           at 25° C.                                                                     0.5 g Water      0.5 g Water                                                  0.12 g  .sub.--N, .sub.--N, .sub.--N.sup.1, .sub.--N.sup.1                                     0.12 g  .sub.--N, .sub.--N, .sub.--N.sup.1,                                   .sub.--N.sup.1 -Tetra-                                       methyl-1,3-propanediamine                                                                      methyl-1,3-propanediamine                                    (2% B.O.R.)                                                                   1.5 g γ-Butyrolactone                                                                    1.5 g 2-Methoxyethyl ether                                                    (inert solvent in place of                                                    γ-Butyrolactone)                                ______________________________________                                               Gardner-Holt                                                                             Centistokes                                                                             Gardner-Holt                                                                           Centistokes                              ______________________________________                                        0      I-J (11/4) 231       I-J (11/3)                                                                             233                                      6.5    K-L        288       J-K      263                                      24     P-Q        418       J-K      263                                      14 Days                                                                              W          1070      L-M      310                                      ______________________________________                                    

EXAMPLE 14

This example was performed to show the effect of using a mixture oflightburned magnesium oxide hardeners of different surface areas. To asolution of 8.0 g Resin A, 0.67 g water, and 2.0 g gama butyrolactone,there was added 1.0 g lightburned magnesia having a surface area of 65m2/g. The mixture was strongly agitated for 1 minute and then 5.0 g ofthe mixture was transferred to each of two small cylindrical plasticvials (22 mm wide) and capped and allowed to stand at 72° F. +/-2° F.for 4 days. The hardened mass was removed from the vials and weighed.The hardened masses were designated as cylinders No. 1 and No. 2. Thesewere then heated for 2 hours at 105° C., weighed and then heated foranother 2 hours 135° C. and reweighed. A similar procedure was followedas above except that an additional 1.0 g of lightburned magnesia havinga surface area of 10 square meters per gram was added to the samequantity of the various ingredients used to prepare cylinders No. 1 andNo. 2 for a total magnesia of 2.0 g per 8 g of Resin A and the samplesdesignated as cylinders No. 3 and No. 4. The results are shown in Table14 wherein the compressive failure was measured on a Tinius Olsentensile test machine. It can be seen from Table 14 that samples withadditional magnesia lose less weight and have higher crush strengthsthan samples with 50% less magnesia. The effect on gel time was minimal,as can be seen in Table 1, Mix 1, in that the mixture of magnesias had agel time of 62 minutes for samples No. 3 and No. 4 as compared to 67minutes for the samples No. 1 and No. 2. Following the same procedure asin this example, various accelerators such as ammonium sulfamate, sodiumchloride, pentane-2,4 -dione, and 2,2¹ -bipyridine can be added to suchcompositions containing mixed surface area magnesium to obtain higherstrength while shortening the time it takes to gel or harden binder,raw, batch, and other compositions of this invention.

                  TABLE 14                                                        ______________________________________                                        Effect of a Mixture of Lightburned Magnesium Oxides                           Having Different Surface Areas in Binder Compositions                         Weight In Grams          Pounds To                                                             2 Hours   2 Hours Compressive                                Cylinder                                                                              Unheated at 105° C.                                                                       at 135° C.                                                                     Failure                                    ______________________________________                                        1       4.99     4.79      4.65    2755                                       2       4.98     4.79      4.65    2855                                       3       4.98     4.85      4.77    3495                                       4       4.96     4.83      4.75    3545                                       ______________________________________                                    

What is claimed is:
 1. A raw batch composition comprising a mixtureof:A. an aggregate material; B. a hardenable phenolic resole resinhaving a pH of about 5 to 9, a resin solids content of about 50% to 90%by weight of said resin, and a viscosity of about 100 to 4,000 cps at25° C.; C. from about 5% to 40% by weight of the resin of a magnesiumhardening agent selected from the group consisting of magnesiumhydroxide and lightburned magnesium oxide, said magnesium oxide having asurface area of at least 10 square meters per gram; D. an accelerator inan amount sufficient to accelerate the hardening of said mixture, saidaccelerator selected from the group consisting of:(a) a2,4-di(dialkylaminomethyl)phenol, a 2,6-di(dialkylaminomethyl)phenol, ora 2,4,6-tris(dialkylaminomethyl)phenol wherein each alkyl group has from1 to 3 carbon atoms; (b) a 1,3,5-tri(loweralkyl)hexahydro-1,3,5-triazine wherein each alkyl group has from 1 to 3carbon atoms; (c) 1,4-diazabicyclo[2.2.2]octane; and (d) a compound ofthe formula: ##STR5## wherein: each of R¹ and R² is a member selectedfrom the group consisting of alkyl having 1 to 3 carbon atoms, and R¹and R² when taken together with the nitrogen to which they are attached,represent a member selected from the group consisting of piperidino,piperazino, morpholino, thiomorpholino, and pyrrolidino; X is a memberselected from the group consisting of (--CH₂ --)_(n) wherein n is aninteger of 1 to 6, --CH═CH--CH₂ --, --CH₂ --CH═CH--CH₂ --, ##STR6## andeach of R³ and R⁴ is a member selected from the group consisting ofhydrogen, alkyl of 1 to 3 carbon atoms, and R³ and R⁴ when takentogether with the nitrogen to which they are attached represent a memberselected from the group consisting of piperazino, morpholino,thiomorpholino, piperidino, and pyrrolidino.
 2. The composition of claim1 wherein: the pH of the resin is from about 5 to 8.5; the quantity ofresin is from about 3% to 20% by weight based on the aggregate; and themixture includes an ester functional hardening agent in an amountsufficient to increase the rate of hardening of the mixture.
 3. Acomposition of claim 2 which has been hardened at ambient temperature.4. The composition of claim 2 wherein: the magnesium hardening agent ismagnesium oxide having a surface area of about 10 to 200 square metersper gram; and the mixture includes fibers in an amount sufficient toimprove the flexural strength of the composition on hardening.
 5. Thecomposition of claim 4 wherein: the aggregate is sand; and thecomposition includes from about 0.1% to 1.5% based on the weight ofresin of a silane adhesion promoter and from about 0.005% to 0.1% an airdetraining agent.
 6. A thermally cured composition of claim
 2. 7. Thecomposition of claim 2 wherein the aggregate is a member selected fromthe group consisting of: refractory grade magnesia; alumina; zirconia;silica; silicon carbide; silicon nitride; boron nitride; bauxite;quartz; corumdum; zircon sand; olivine sand; and mixtures thereof. 8.The composition of claim 2 wherein the phenolic resole resin is thecondensation product of phenol and formaldehyde.
 9. The composition ofclaim 7 which further includes from about 5% to 25% of graphite based onthe weight of the aggregate and from about 1% to 5% by weight of theaggregate of a metal powder selected from the group consisting ofaluminum, magnesium, and silicon.
 10. A composition of claim 9 which hasbeen hardened at ambient temperature.
 11. A composition of claim 9 whichhas been thermally cured.
 12. The composition of claim 1 wherein themagnesium hardening agent is lightburned magnesium oxide.
 13. Thecomposition of claim 12 wherein X in the formula ##STR7## is alkylenehaving from 1 to 6 carbon atoms.
 14. The composition of claim 12 whereinthe accelerator is a 2,4,6-tris(dialkylaminomethyl)phenol having from 1to 3 carbon atoms in each alkyl group.
 15. The composition of claim 12wherein the accelerator is 1,3,5-tri(lower alkyl)hexahydro-1,3,5-triazine wherein each alkyl group has from 1 to 3 carbonatoms.
 16. The composition of claim 12 wherein the accelerator is1,4-diazabicyclo[2.2.2]octane.
 17. A raw batch composition comprising amixture of:A. an aggregate material; B. a hardenable phenolic resoleresin having a pH of about 4.5 to 9.5, a solids content of about 50% to90% by weight of the resin, and a viscosity of about 100 to 4,000 cps at25° C.; C. from about 5% to 50% by weight of the resin of lightburnedmagnesium oxide having a surface area of at least about 10 square metersper gram; and D. from about 0.5% to 5% by weight of the resin of anaccelerator compound which has a water solubility of at least 1% byweight at 25° C. and provides to the mixture an accelerator selectedfrom the group consisting of:(a) a 2,4-di(dialkylamonomethyl)phenol, a2,6-di(dialkylaminomethyl)phenol, or a2,4,6-tris(dialkylaminomethyl)phenol wherein each alkyl group has from 1to 3 carbon atoms; (b) a 1,3,5-tri(lower alkyl)hexahydro-1,3,5-triazinewherein each alkyl group has from 1 to 3 carbon atoms; (c)1,4-diazabicyclo[2.2.2]octane; and (d) a compound of the formula:##STR8## each of R¹ and R² is a member selected from the groupconsisting of alkyl having 1 to 3 carbon atoms, and R¹ and R² when takentogether with the nitrogen to which they are attached, represent amember selected from the group consisting of piperidino, piperazino,morpholino, thiomorpholino, and pyrrolidino; X is a member selected fromthe group consisting of (--CH₂ --)_(n) wherein n is an integer of 1 to6, --CH═CH--CH₂ --, --CH₂ --CH═CH--CH₂ --, ##STR9## each of R³ and R⁴ isa member selected from the group consisting of hydrogen, alkyl of 1 to 3carbon atoms, and R³ and R⁴ when taken together with the nitrogen towhich they are attached represent a member selected from the groupconsisting of piperazino, morpholino, thiomorpholino, piperidino, andpyrrolidino.
 18. The composition of claim 17 wherein the accelerator is2,4,6-tris(dimethylaminomethyl)phenol.
 19. The composition of claim 17wherein: the pH of the resin is from about 5 to 8.5; and the mixtureincludes an ester functional hardening agent in an amount sufficient toincrease the rate of hardening of the mixture, said ester functionalhardening agent selected from the group consisting of a lactone, acyclic organic carbonate, a carboxylic acid ester, and mixtures thereof.20. The composition of claim 19 wherein the ester is a lactone.